Question

the chloroplasts of green algae and land plants have two membranes. these chloroplasts were acquired through endocytosis of a cyanobacterium containing chlorophyll and possessing a double membrane. what two events would explain why the chloroplasts of euglenids (a unicellular clade) have three membranes yet contain the same photosynthetic pigments as both green algae and land plants? the ancestral euglenid engulfed a green alga through secondary endosymbiosis, while a different green alga became the ancestor to plants. green plants engulfed a photosynthetic euglenid and were ancestral to green algae. ancestral green algae engulfed a euglenid through secondary endosymbiosis and gave rise to green plants. plants arose from green algae and engulfed a euglenid to acquire photosynthetic pigments. ancestral green plants arose from euglenids and then engulfed photosynthetic green algae.

Explanation:

The chloroplasts of green algae and land - plants have two membranes because they acquired them through endocytosis of a cyanobacterium. Euglenids have three membranes around their chloroplasts as they acquired them through secondary endosymbiosis where the ancestral euglenid engulfed a green alga. Green plants became the ancestor to plants after ancestral green algae engulfed a photosynthetic euglenid and were ancestral to green algae.

Answer:

The ancestral euglenid engulfed a green alga through secondary endosymbiosis, while a different green alga became the ancestor to plants.