D. Increased porosity (allows extra oxygen and water)
Do you mean electron? If so they are molecules that transport electrons during cellular respiration.
Climate change
Greenhouse effect
Some heat energy from the Earth’s surface escapes into space. If too much heat energy escaped, the planet would be very cold. However some gases in the atmosphere can trap escaping heat energy, causing some of it to pass back to the surface.
These are called greenhouse gases, and they keep our planet warm, which is a good thing. Carbon dioxide is an important greenhouse gas.
Increasing carbon dioxide levels
Humans burn fossil fuels such as oil, coal and natural gas. The energy released is used to power cars and other machines, to generate electricity, and to keep buildings warm. The burning fuel releases waste gases, including carbon dioxide. As the human population increases, more fuel is used, and more carbon dioxide is released.
Global warming
The extra carbon dioxide increases the greenhouse effect. More heat is trapped by the atmosphere, causing the planet to become warmer than it would be naturally. The increase in global temperature this causes is called global warming.
Well either way, it would be difficult for them to find mates, but if 50% of males were gone, the females would be able to reproduce with the men they have but if the females were killed off, it would affect birth rates even worse because the women carry the offspring. All of this also includes the offspring's gender
