A. Weathering is the correct answer
Cell surface or membrane is made of phospholipid bilayer with embedded proteins and sugars. Cell membrane acts as a barrier between cell and its external environment but it is also responsible for the communication with other cells and transport of molecules inside and outside the cell. It is selectively permeable to ions and molecules (some of them pass through the membrane easily, while others require transport proteins or channels). There are 4 ways of molecule transport:
1. Diffusion – no energy required
2. Facilitated transport – transport proteins included
3. Active and co-transport – energy required
4. Vesicle transport (exocytosis and endocytosis)
Microvilli are extensions of cell membrane that increase its surface for diffusion.
Different types of cell junctions have a different influence on the membrane transport. For example, tight junctions are a barrier and the molecules are unable to pass through.
Monosaccharides and disaccharides are relatively small molecules. They are often called sugars.
Answer:
The unified cell theory states that: all living things are composed of one or more cells; the cell is the basic unit of life; and new cells arise from existing cells.
Therefore, B is the answer.
"All living cells require water for survival" is NOT a statement from the cell theory.
Answer:
(1) as organic molecules in living and dead organisms found in the biosphere; (2) as the gas carbon dioxide in the atmosphere
Explanation:
