Maria walks up hill to go to school every day. When she reaches the top of the hill, she is always breathing much faster than when she started. How might this affect how her heart is working? Support your hypothesis with evidence.

''By doing hard activity, the pumps very fast.''

Explanation:

''By doing hard activity, the heart pumps very fast.'' is my hypothesis. In this hypothesis, I mentioned that during hard activity pumping of heart goes very fast because our body needs oxygen as well as energy in the form of ATP and the only way to get both oxygen and energy is the pumping of heart which supply oxygen to the cell as a result energy is generated in the form of ATP and removes carbondioxide gas by breathing.

step 1: nitrogen fixation- conversion of atmospheric no₂ into forms useful to plants by lightning, bacteria, and cyanobacteria.

step 2: nitrification-process of converting ammonia to nitrite or nitrate.

step 3: assimilation-plant roots absorb new form of nitrogen.

step 4: ammonification-conversion of organic nitrogen to ammonia by bacteria involved in decomposition.

step 5: denitrification-bacteria turns the decomposed matter back into n₂o, which is released into atmosphere; repeat cycle.