D, different species in the world
The ecosystem is an ecological system consisting of all of its biotic and abiotic factors
Answer:
The definition of trade off is an exchange where you give up one thing in order to get something else that you also desire. An example of a trade off is when you have to put up with a half hour commute in order to make more money.
Explanation:
<span>nerve cells need b 12 for proper functioning</span>
That their ancestors were related