D there is competition between species
The variable that is intentionally manipulated or changed in a controlled experiment is know as the B) Independent Variable.
This is done, as the question states, to test the hypothesis. In other words, it is changed in order to see what results are produced, then the results are analyzed, and ideally an explanation of the changing results will arise and progress can be made in the experiment.
Answer:
the dna for all organisms is commen because almost every living thing had dna from both there mother and father
Explanation:
Answer:
Most organisms cannot obtain nitrogen from the atmosphere. Nitrogen fixing bacteria take Nitrogen out of the atmosphere and make it available for consumption by the other organisms, This is important because Nitrogen is an essential building block of life.
Mesozoic, the era contained both large reptiles and small birds/mammals. It's interesting, coming from an evolutionary biology.
Hope this helped!
