Question

which statement best describes the endosymbiont theory? it suggests that all organelles in eukaryotic cells formed independently within the cell. it claims that organelles in eukaryotic cells are formed only through mutation and natural selection. it states that eukaryotic cells evolved directly from prokaryotic cells without any symbiosis. it proposes that small bacteria began were engulfed and begin living inside larger cells and eventually became organelles.

Explanation:

The endosymbiont theory describes how eukaryotic cells evolved from a symbiotic relationship between small prokaryotic organisms (like bacteria) and larger host cells. The smaller cells were engulfed but not digested, instead living inside the host and eventually developing into specialized organelles (such as mitochondria and chloroplasts). The other options do not match this core concept: the first option incorrectly states organelles formed independently within the cell, the second claims organelles formed only via mutation/selection, and the third says eukaryotes evolved directly from prokaryotes without symbiosis.

Answer:

It proposes that small bacteria were engulfed and begin living inside larger cells and eventually became organelles.