Ok, think about it. Does your skin prevent germs from getting inside you?
Does your skin prevent water from leaving the body too quickly? Does your skin protect your insides from getting damaged when you fall? Do you put food on your skin to absorb nutrients, or do you put food in your mouth like a normal person?
Cells are the basic structural, functional, and biological unit of all known living organisms. Cells of various types have different functions but the generalized cell functions include movement of substances across the cell membrane, cell division to make new cells, and protein synthesis. So, the answer is D, cell can conduct many tasks, including duplicate themselves, convert energy and selectively exchange materials.
A clade is a group of species that includes an ancestral species and all of its descendents
The square denotes male. One parent is recessive, so X must have at least one recessive allele. B is the right answer.