Answer:
d is the correct answer of your question
At the smallest level of organization, the DNA wraps itself around small globular proteins called histones. Complexes of histones and DNA form nucleosomes, which appear as "beads" on the DNA strand. Chromatin refers to the decondensed DNA that has not formed separate chromosomes.
Plankton is at the bottom of a food chain. Think of a pond. Mosquito larvae are in a pond. They eat the plankton. Small fish eat the larvae. Larger fish eat those smaller fish and the chain keeps going..BUTTT it all started with the PLANKTON. Without the plankton the whole food chain would be messed up and everything would start dying.. No plankton, no larvae, no small fish..and so on..
It takes the Earth (approximately) 364.25 days to revolve around the sun. That's why we have leap days.
Hope that helps!