I think that carbon dioxide/pollution could be a massive change in the environment. You can find more information here
http://www.theworldcounts.com/stories/How-Pollution-Affects-the-Environment
Answer:
Oxygen is essential to enabling many of the Earths life forms to survive -- without access to oxygen, humans cant live for more than a few minutes. The air that enters human lungs contains about 21 percent oxygen. The process responsible for producing most of the Earths oxygen is known as photosynthesis. In this process, plants and certain other organisms convert sunlight into oxygen and other products.
Explanation:
If i remember correctly they should be adenine (A), thymine (T), guanine (G) and cytosine (C). i hope this helps. sorry if they arent all correct.
An enzyme is a kind of catalyst. Hope this helps:-)
A timot in biology is an abnormal mass of tissue that results from excessive cell division that is uncontrolled and progressive, also called a neoplasm. Tumours perform no useful body function. They may be either benign (not cancerous) or malignant.