D - an increase in tree cover in the tundra.
I think the correct answer from the choices listed above is option B. You can find methanogens in the human intestines. These organisms can work with or without oxygen. Too much of oxygen for them is toxic. They are obligate anaerobes.
Answer:
evaporation follows condensation
The nitrogen is captured and converted into a form that is usable by plants in a process called
<span>nitrogen fixation</span>
The basic structure of a steroid differ from other macromolecules such as carbohydrates by having a four ring structure whereas a carbohydrate do not have. A steroid is a group of organic substances which has four rings that are arranged in a certain configuration. Examples are testosterone, estradiol and lipid cholesterol. It will always have seventeen carbon atoms in its structure. Carbohydrates, on the other hand, are a group of organic substances that consist carbon, hydrogen and oxygen atoms typically in a 2:1 ratio of the hydrogen and oxygen atoms. So, it would have an empirical formula of Cx(H2O)y.
