<span>The answer is nitrogen. Plants cannot use atmospheric nitrogen directly. Nitrogen from the air must be converted into the different form so plants can absorb it. Thus plants need nitrogen-fixing bacteria to convert atmospheric nitrogen into ammonium, which is available for plants to absorb it. </span>
Answer:A
Explanation:
The meaning of evolution-the process by which different kinds of living organisms are thought to have developed and diversified from earlier forms during the history of the earth.
So, B is incorrect since it is talking of the present. C, shows the growing of hair, but has no answer to evolution, since it does not show an organism growing from the past to present. D, shows evolution of land but no “living organism”
In conclusion, the best answer is A.
This statement is true. Plaque is considered dangerous because it can break off and create a clot in the arteries. one of the most common results of this is heart attack.
The answer is serotonin. Serotonin is a significant chemical neurotransmitter in the human body. Serotonin that is used in the brain must be made within it. It is believed that serotonin can touch mood and social performance, hunger and ingestion, slumber, reminiscence and sensual desire and purpose.
A. Enzymes speed up chemical reactions because the time needed to activate the reaction is lowered.