Answer:
Cells divide so living things can grow. When organisms grow, it isn't because cells are getting larger. Organisms grow because cells are dividing to produce more and more cells.
Answer:
1. The animal can't see what happening behind its head.
2. Head can be moved upto 180 degree angle in most of the animals including humans. But it is not true in case of birds.
Explanation:
These unsegmented worms have a full digestive system even when parasitic.
The change in intractellular pH can potentially affect virtually all cellular processes. It includes metabolism, membrane potential, cell growth, movement of substance across of surface membrane, state of polymerization of the cytoskeleton and the ability to contract in muscle cell
I think you're confused. There are only two sexes, male and female. Sex is what you were biologically born as from birth, while gender is what you choose to identify as. Gender is a choice, sex isn't. They couldn't discover any other genders because at the time they probably didn't even know what gender was like three thousand years ago, therefore they couldn't look like a different gender.