Answer:
Mutualism
Explanation:
Mutualism: is a relationship between individuals of different species in which both individuals benefit from each other without causing no harm. Example is the nitrogen-fixing bacteria and plants.
Answer:
if we`ll not classify living beings then it`ll become difficult to study all of beings one by one. In order to make their study easier biologists have classified all living beings into five major groups.
Explanation:
Acne is to excessive secretion of oil
(D)an atom can join with other kinds of atoms.
Basically he explained what a molecule is.