The answer is A: Mass extinction.
"Abrupt disappearance of many land and marine species" = extinction of many species.
They become more large and are less able to divide and multiply.Which as an increase in pigment and a fatty substance inside the cell . (Hopes this helped)
The best answer is A. The purpose of the cell wall is to hold the cell in a specific shape, usually rectangular or square. For example, a plant cell's wall keeps it rigid so that the plant can stand up.
If the cell does not have a wall, it can easily change shape to accommodate for things coming in and out of the cell.
Hope this helps!
B. The amount of waste would build up and the toxins produced would harm the animals and humans
