Answer:
A cell may vary the rate of an enzyme controlled reaction by making more/less or degrading more/less.
Explanation:
A cell may vary the rate of an enzyme controlled reaction by making more/less or degrading more/less. Several factors affect the rate at which enzymatic reactions proceed include post translational modifications, substrate concentration, cofactors, temperature, pH, locations. The shape and structure of the enzyme will change as the pH value of the reaction medium changes.
Pumping blood throughout the cardiovascular system
C<span>ondensation plays a significant role in the formation of clouds. </span>
Facilitated diffusion. It is a passive transport mechanism in which carrier proteins shuttle molecules across the cell membrane without using the cell’s energy supplies. Instead, the energy is provide by the concentration gradient, which means that molecules are transported from higher to lower concentrations, into or out of the cell. The carrier proteins bind to glucose, which causes them to change shape and translocate the glucose from one side of the membrane to the other. Red blood cells use facilitated diffusion to absorb glucose.
Answer:

Explanation:
An element only has <u>one</u> type of atom and cannot be broken down by chemical means.
Let's analyze the answer choices.
1. This has two types of atoms, so it cannot be an element. It has more than one type of atom.
2. This has two types of atoms that are bonded together. It cannot be an element because there is more than one type of atom and the bonds can be broken.
3. This has one type of atoms, so it is an element.
Therefore the best answer choice is 3.