Question

Chloroplasts were once ___________ that took up residence inside an ancestor of some eukaryotic lineages?

Answer 1

Chloroplasts were once photosynthetic bacteria that took up residence inside an ancestor of some eukaryotic lineages. This concept is known as the endosymbiotic theory.

Step-by-step explanation:

Chloroplasts were once photosynthetic bacteria that took up residence inside an ancestor of some eukaryotic lineages. This concept is known as the endosymbiotic theory, which suggests that chloroplasts originated from ancestral photosynthetic bacteria that lived symbiotically inside a eukaryotic cell. The chloroplasts contain the green pigment chlorophyll and play a crucial role in photosynthesis.