Answer:
signal molecule is a general term for molecules also called (ligands)that bind specifically to other molecules (such as receptors). hope it helps!!
Natural selection doesn't favor traits that are somehow inherently superior. Instead, it favors traits that are beneficial (that is, help an organism survive and reproduce more effectively than its peers) in a specific environment. Traits that are helpful in one environment might actually be harmful in another.
(one again, I hope this helps ^^)
a) ribosomes on the rough endoplasmic reticulum
mRNA (created by DNA) leaves the nucleus through the nucleic pores, and from there will enter a nearby ribosome since the rough endoplasmic reticulum is surrounding the nucleus. It is there that polypeptides are made and transported in vesicles to the Golgi apparatus because they cannot touch the cytoplasm when still incomplete. Hope this helped.
Answer:
These four subsystems are called "spheres." Specifically, they are the "lithosphere" (land), "hydrosphere" (water), "biosphere" (living things), and "atmosphere" (air). Each of these four spheres can be further divided into sub-spheres.