Todas as questões do ENEM

A maior parte das características dos seres vivos resulta da ação de diversos genes, que interagem na determinação da característica. Quando dois ou mais genes, localizados ou não no mesmo cromossomo, agem conjuntamente na determinação de uma característica fala- se em:

A teoria moderna da evolução ou teoria sintética da evolução considera três fatores evolutivos principais:

Considere apenas as “ideias modernas sobre a origem da vida”.

I – Alguns tipos de seres vivos podiam ser gerados espontaneamente a partir da matéria sem vida, ou mesmo pela transformação de outros seres vivos.

II – A maioria dos cientistas defende a chamada teoria da evolução molecular, segundo a qual a vida surgiu após um longo processo de transformações químicas.

III – Os seres vivos surgem somente pela reprodução de seres de sua espécie.

São afirmativas corretas:

Dos fatores abaixo relacionados, apenas um deles, se aumentado, provoca diminuição na velocidade de uma reação química. O referido fator será:

Considere uma solução aquosa saturada de KNO₃ a 20°C, com precipitado de fundo, e os seguintes valores:

Assinale a alternativa correta para o cálculo da matriz abaixo, determinando o valor de X e Y de modo que se tenha A = B.

Monique brincava com um dado quando resolveu analisar a probabilidade de tirar um número primo ao jogar o objeto para cima. Verificando o dado após sua jogada, foi obtida face com número maior que 2. Logo, a probabilidade deste número ser primo está na alternativa:

Estudando probabilidade, Vicente se deparou com uma relação de quatro exercícios já resolvidos. Após conferência dos cálculos, descobriu um erro no exercício citado na alternativa:

Analise as sentenças abaixo e assinale a única correta.

I- Os poliedros são formas espaciais sólidas delimitadas por superfícies planas poligonais. Uma superfície poligonal corresponde a um polígono reunido com a parte do plano em seu interior.

II- Os poliedros possuem algumas características e uma delas é que eles são limitados por superfícies planas poligonais chamadas de faces do poliedro.

III- As superfícies poligonais que delimitam o poliedro interceptam-se em lados dos polígonos. Esses segmentos são chamados de arestas do Poliedro.

IV-O cubo é um poliedro cujas arestas constam com diferentes tamanhos em um único cubo.

Can talking on a mobile phone be hazardous to your health? It is difficult to know for sure. Some research suggests that heavy users of mobile phones are at a greater risk of developing cancerous brain tumours. However, many other studies suggest there are no links between cancer and mobile phone use.

The main problem with the current research is that mobile phones have only been popular since the 1990s. As a result, it is impossible to study long-term exposure to mobile phones. This concerns many health professionals who point out that certain cancers can take over twenty years to develop. Another concern about these studies is that many have been funded by the mobile phone industry or those who benefit from it.

Over five billion people now use mobile phones on a daily basis, and many talk for more than an hour a day. Mobile phone antennas are similar to microwave ovens. While both rely on electromagnetic radiation (EMR), the radio waves in mobile phones are lower in frequency. Microwave ovens have radio wave frequencies that are high enough to cook food, and they are also known to be dangerous to human tissues like those in the brain. The concern is that the lowerfrequency radio waves that mobile phones rely on may also be dangerous. It seems logical that holding a heat source near your brain for a long period of time is a potential health hazard.

Some researchers believe that other types of wireless technology may also be dangerous to human health, including cordless phones, wireless gaming consoles, and laptop or tablet computers with wireless connections. They suggest replacing all cordless and wireless devices with wired ones where possible. They also say that many cordless phones can emit dangerous levels of Electromagnetic Radiation even when they are not in use. They even suggest keeping electronic devices such as desktop and tablet computers out of the bedroom, or at least six feet from the head while we're sleeping.

A growing number of health professionals worldwide are recommending that mobile phone users err on the side of caution until more definitive studies can be conducted. They use the example of tobacco to illustrate the potential risks. Many years ago, people smoked freely and were not concerned about the effects of cigarettes on their health. Today, people know that cigarettes cause lung cancer, though it is still unknown exactly how or why. Some doctors fear that the same thing will happen with mobile phones. In May 2016, the UK's Independent newspaper reported on research by the US government's National Toxicology Program that showed a slight increase in brain tumours among rats exposed to the type of radio frequencies commonly emitted by mobile phones. This doesn't prove that mobile phones can cause brain tumours in humans, but it does show that it's possible. As a result, many experts now recommend texting or using head sets or speaker phones instead of holding a mobile phone to the ear.

From the sentence “mobile phones have only been popular since the 1990s", it is possible to understand that:

Can talking on a mobile phone be hazardous to your health? It is difficult to know for sure. Some research suggests that heavy users of mobile phones are at a greater risk of developing cancerous brain tumours. However, many other studies suggest there are no links between cancer and mobile phone use.

The main problem with the current research is that mobile phones have only been popular since the 1990s. As a result, it is impossible to study long-term exposure to mobile phones. This concerns many health professionals who point out that certain cancers can take over twenty years to develop. Another concern about these studies is that many have been funded by the mobile phone industry or those who benefit from it.

Over five billion people now use mobile phones on a daily basis, and many talk for more than an hour a day. Mobile phone antennas are similar to microwave ovens. While both rely on electromagnetic radiation (EMR), the radio waves in mobile phones are lower in frequency. Microwave ovens have radio wave frequencies that are high enough to cook food, and they are also known to be dangerous to human tissues like those in the brain. The concern is that the lowerfrequency radio waves that mobile phones rely on may also be dangerous. It seems logical that holding a heat source near your brain for a long period of time is a potential health hazard.

Some researchers believe that other types of wireless technology may also be dangerous to human health, including cordless phones, wireless gaming consoles, and laptop or tablet computers with wireless connections. They suggest replacing all cordless and wireless devices with wired ones where possible. They also say that many cordless phones can emit dangerous levels of Electromagnetic Radiation even when they are not in use. They even suggest keeping electronic devices such as desktop and tablet computers out of the bedroom, or at least six feet from the head while we're sleeping.

A growing number of health professionals worldwide are recommending that mobile phone users err on the side of caution until more definitive studies can be conducted. They use the example of tobacco to illustrate the potential risks. Many years ago, people smoked freely and were not concerned about the effects of cigarettes on their health. Today, people know that cigarettes cause lung cancer, though it is still unknown exactly how or why. Some doctors fear that the same thing will happen with mobile phones. In May 2016, the UK's Independent newspaper reported on research by the US government's National Toxicology Program that showed a slight increase in brain tumours among rats exposed to the type of radio frequencies commonly emitted by mobile phones. This doesn't prove that mobile phones can cause brain tumours in humans, but it does show that it's possible. As a result, many experts now recommend texting or using head sets or speaker phones instead of holding a mobile phone to the ear.

Considering the text, fill the parenthesis with T (true) or F (false):

( ) One of the problems of current research on the hazards of mobile phones is that they have been popular for too long, which creates a lot of data do be analyzed.

( ) Regarding the risks mobile phones can pose to our health, health professionals worldwide believe it is better to be cautious until more conclusive research is conducted.

( ) The frequency used by mobile phones is significantly higher than the frequency of microwaves, hence the health problems.

( ) Health professionals use the example of the tobacco industry to illustrate that mobile phones can be dangerous, even though research is still not conclusive on that.

The correct sequence, from top to bottom is:

Can talking on a mobile phone be hazardous to your health? It is difficult to know for sure. Some research suggests that heavy users of mobile phones are at a greater risk of developing cancerous brain tumours. However, many other studies suggest there are no links between cancer and mobile phone use.

The main problem with the current research is that mobile phones have only been popular since the 1990s. As a result, it is impossible to study long-term exposure to mobile phones. This concerns many health professionals who point out that certain cancers can take over twenty years to develop. Another concern about these studies is that many have been funded by the mobile phone industry or those who benefit from it.

Over five billion people now use mobile phones on a daily basis, and many talk for more than an hour a day. Mobile phone antennas are similar to microwave ovens. While both rely on electromagnetic radiation (EMR), the radio waves in mobile phones are lower in frequency. Microwave ovens have radio wave frequencies that are high enough to cook food, and they are also known to be dangerous to human tissues like those in the brain. The concern is that the lowerfrequency radio waves that mobile phones rely on may also be dangerous. It seems logical that holding a heat source near your brain for a long period of time is a potential health hazard.

Some researchers believe that other types of wireless technology may also be dangerous to human health, including cordless phones, wireless gaming consoles, and laptop or tablet computers with wireless connections. They suggest replacing all cordless and wireless devices with wired ones where possible. They also say that many cordless phones can emit dangerous levels of Electromagnetic Radiation even when they are not in use. They even suggest keeping electronic devices such as desktop and tablet computers out of the bedroom, or at least six feet from the head while we're sleeping.

A growing number of health professionals worldwide are recommending that mobile phone users err on the side of caution until more definitive studies can be conducted. They use the example of tobacco to illustrate the potential risks. Many years ago, people smoked freely and were not concerned about the effects of cigarettes on their health. Today, people know that cigarettes cause lung cancer, though it is still unknown exactly how or why. Some doctors fear that the same thing will happen with mobile phones. In May 2016, the UK's Independent newspaper reported on research by the US government's National Toxicology Program that showed a slight increase in brain tumours among rats exposed to the type of radio frequencies commonly emitted by mobile phones. This doesn't prove that mobile phones can cause brain tumours in humans, but it does show that it's possible. As a result, many experts now recommend texting or using head sets or speaker phones instead of holding a mobile phone to the ear.

Can talking on a mobile phone be hazardous to your health? It is difficult to know for sure. Some research suggests that heavy users of mobile phones are at a greater risk of developing cancerous brain tumours. However, many other studies suggest there are no links between cancer and mobile phone use.

The main problem with the current research is that mobile phones have only been popular since the 1990s. As a result, it is impossible to study long-term exposure to mobile phones. This concerns many health professionals who point out that certain cancers can take over twenty years to develop. Another concern about these studies is that many have been funded by the mobile phone industry or those who benefit from it.

Over five billion people now use mobile phones on a daily basis, and many talk for more than an hour a day. Mobile phone antennas are similar to microwave ovens. While both rely on electromagnetic radiation (EMR), the radio waves in mobile phones are lower in frequency. Microwave ovens have radio wave frequencies that are high enough to cook food, and they are also known to be dangerous to human tissues like those in the brain. The concern is that the lowerfrequency radio waves that mobile phones rely on may also be dangerous. It seems logical that holding a heat source near your brain for a long period of time is a potential health hazard.

Some researchers believe that other types of wireless technology may also be dangerous to human health, including cordless phones, wireless gaming consoles, and laptop or tablet computers with wireless connections. They suggest replacing all cordless and wireless devices with wired ones where possible. They also say that many cordless phones can emit dangerous levels of Electromagnetic Radiation even when they are not in use. They even suggest keeping electronic devices such as desktop and tablet computers out of the bedroom, or at least six feet from the head while we're sleeping.

A growing number of health professionals worldwide are recommending that mobile phone users err on the side of caution until more definitive studies can be conducted. They use the example of tobacco to illustrate the potential risks. Many years ago, people smoked freely and were not concerned about the effects of cigarettes on their health. Today, people know that cigarettes cause lung cancer, though it is still unknown exactly how or why. Some doctors fear that the same thing will happen with mobile phones. In May 2016, the UK's Independent newspaper reported on research by the US government's National Toxicology Program that showed a slight increase in brain tumours among rats exposed to the type of radio frequencies commonly emitted by mobile phones. This doesn't prove that mobile phones can cause brain tumours in humans, but it does show that it's possible. As a result, many experts now recommend texting or using head sets or speaker phones instead of holding a mobile phone to the ear.

Can talking on a mobile phone be hazardous to your health? It is difficult to know for sure. Some research suggests that heavy users of mobile phones are at a greater risk of developing cancerous brain tumours. However, many other studies suggest there are no links between cancer and mobile phone use.

The main problem with the current research is that mobile phones have only been popular since the 1990s. As a result, it is impossible to study long-term exposure to mobile phones. This concerns many health professionals who point out that certain cancers can take over twenty years to develop. Another concern about these studies is that many have been funded by the mobile phone industry or those who benefit from it.

Over five billion people now use mobile phones on a daily basis, and many talk for more than an hour a day. Mobile phone antennas are similar to microwave ovens. While both rely on electromagnetic radiation (EMR), the radio waves in mobile phones are lower in frequency. Microwave ovens have radio wave frequencies that are high enough to cook food, and they are also known to be dangerous to human tissues like those in the brain. The concern is that the lowerfrequency radio waves that mobile phones rely on may also be dangerous. It seems logical that holding a heat source near your brain for a long period of time is a potential health hazard.

Some researchers believe that other types of wireless technology may also be dangerous to human health, including cordless phones, wireless gaming consoles, and laptop or tablet computers with wireless connections. They suggest replacing all cordless and wireless devices with wired ones where possible. They also say that many cordless phones can emit dangerous levels of Electromagnetic Radiation even when they are not in use. They even suggest keeping electronic devices such as desktop and tablet computers out of the bedroom, or at least six feet from the head while we're sleeping.

A growing number of health professionals worldwide are recommending that mobile phone users err on the side of caution until more definitive studies can be conducted. They use the example of tobacco to illustrate the potential risks. Many years ago, people smoked freely and were not concerned about the effects of cigarettes on their health. Today, people know that cigarettes cause lung cancer, though it is still unknown exactly how or why. Some doctors fear that the same thing will happen with mobile phones. In May 2016, the UK's Independent newspaper reported on research by the US government's National Toxicology Program that showed a slight increase in brain tumours among rats exposed to the type of radio frequencies commonly emitted by mobile phones. This doesn't prove that mobile phones can cause brain tumours in humans, but it does show that it's possible. As a result, many experts now recommend texting or using head sets or speaker phones instead of holding a mobile phone to the ear.