I think it is the cell membrane, but there is a possibility it is the cell wall. I think the cell membrane is correct because the skin does allow certain things into your skin cells, such as water. Similarly, cell membranes allow certain things in the cell. The cell membrane basically acts as the security guard of the cell.
Limited jurisdiction, i.e. applicable only to traffic cases.
A heterogeneous mixture is a mixture in which its components retain their identity (texture, surface tension, etc.)
B. Raise income taxes in all us people in the US
B- copper and zinc; I had to answer that question yesterday on my quiz
