The theory of endosymbiosis is based on Multiple Choice similarities between chloroplasts and other organelles in animals. evidence from the fossil record. the knowledge that ribosomes are structures found in bacteria, plants, and animals. the experiments in which bacteria were made to grow in plant cells forming chloroplasts. the observations that chloroplasts and mitochondria resemble bacteria.

the observations that chloroplasts and mitochondria resemble bacteria

Explanation:

The Endosymbiotic Theory is a theory that enables us to understand the origin of eukaryotic cells. The Endosymbiotic Theory posits that the mitochondria and chloroplast, which are organelles found in the eukaryotic cells, were once prokaryotic microbes that were first ingested by amoeba-like organisms and subsequently evolved by developing a symbiotic relationship with them. Some of the most important lines of evidence that supports this theory are: 1-chloroplasts and mitochondria resemble prokaryotic cells, i.e., they have a similar size, replicate by binary fission and there are unicellular eukaryotic protists that have filamentous temperature-sensitive proteins at their division plane (similarly to bacteria), and 2- chloroplasts and mitochondria are organelles with their own DNA and their own ribosomes (which are similar to those of bacteria).

the observations that chloroplasts and mitochondria resemble bacteria

Explanation:

Replication. Mitochondria and chloroplasts make more of themselves in much the same way as bacteria reproduce. ... Like bacteria, mitochondria and chloroplasts grow in size, duplicate their DNA and other structures, and then divide into two identical organelles.

not too sure but maybe in the hot springs.