Answer: A.) The nitrogen cycle recycles nitrogen through an ecosystem, making it available to all organisms.
Explanation: Nitrogen is an essential nutrient for plants and a significant component of proteins, which all animals need to grow, reproduce and survive. The nitrogen cycle converts nitrogen into compounds that plants and animals can use.
The correct answer is D. Homeostasis and transport of molecules
Explanation:
The diagram presented shows the movement of glucose from outside the cell to inside it. Also, this diagram illustrates this process occurs through the cell membrane and there is a higher concentration outside the cell.
This complex process illustrates the transport of molecules in the cell, which refers to a mechanism that allows molecules and substances to move in and out of a cell. Moreover, this process implies molecules (in this case glucose) move to one area with a lower concentration to preserve equilibrium as shown by the diagram. Additionally, this equilibrium is part of homeostasis which is a set of mechanisms to main an equilibrium in the cell, including appropriate levels of glucose and other substances.