It is mostly likely the cell membrane.
The cell membrane is a structure of a cell composed of double layer of lipids and proteins. It surrounds a cell and separates the cytoplasm from its surrounding environment. The cell membrane is selectively permeable (semi-permeable), which means that it only lets certain molecules enter and exit. It can also control the amount of some substances that go into or out of the cell.
A Pollen Cell is called a Generative Cell
The answer is D because the particles in a liquid have more kinetic energy than the particles in the corresponding solid.
All of these are essential to survive
