Answer:
endosymbiosis.
Explanation:
By the beginning of the 20th century, researchers thought that plastids and mitochondria could come from bacteria. These would have been ingested by primitive cells and live within them in symbiosis.
A hypothesis<span> is an idea that </span>can be tested<span> by an </span>experiment<span>-These ideas are based upon a person's </span>observations and<span> previous knowledge or experience. </span>
Mutualism, commensalism and parasitism
