Answer:
A. ocean trenches
Explanation:
I just took that test. Sorry I know I'm late and this won't help.
Mutation...are there answer choices?
In 1775 Jenner began to study the relationship between cowpox (a comparatively harmless disease) and the more dangerous and disfiguring smallpox. ... He hypothesized that exposure to cowpox rendered the body immune from smallpox. After nearly twenty years of experiments, he developed the first vaccine.
Answer:
A) Plant Cells
Explanation
Cell walls are only found in plant cells and are used primarily to create structure, but cell membranes are found in all cells.The bulk of the membrane is composed of a double layer of lipids called the lipid bilayer. Inside the bilayer there is a layer of cholesterol to keep the membrane fluid.
