Answer:
The answer is "form only at boundaries between two continental plates." :)
Diatoms contain chloroplasts that have four membranes. These four membranes are evidence of secondary endosymbiosis (Option c).
<h3>What is secondary endosymbiosis?</h3>
Secondary endosymbiosis is a hypothesis used to explain why diatom chloroplasts have four membranes.
According to this hypothesis, diatoms received different genes from distinct photosynthetic and non-photosynthetic ancestors.
The acquisition of genes of different ancestors led to diatoms having chloroplasts with four membranes.
Learn more about the endosymbiosis hypothesis here:
brainly.com/question/2957447
They are all rock with different size and shapes and are located in different areas possibly in the same areas but they all have there own unique textures from the photographs and 3 of them look like maybe a fossil of some type of when the dinosaurs where still around and the rocks on the top left corner look smooth and are a small type of igneous rocks. That have been soothed over the years.
