B. Mutations cause a person's body cells to divide uncontrollably. There isn't a signal for cells to stop dividing, so this can cause cancer because cancer cells won't stop dividing without this signal.
A cell membrane pump helps human cells to maintain a relatively constant sodium and potassium concentration.
<u>Option: A</u>
<u>Explanation:</u>
Sodium potassium pump is a plasma membrane protein that utilizes energy ATP — Triphosphate Adenosine turning into ADP — Adenosine Diphosphate to deliver intracellular and extracellular sodium (NA+) and potassium (K+) ions sequentially. The purpose of this entire mechanism is to preserve cell equilibrium.
The extracellular medium has a greater concentration of Na while the K concentration of the intracellular fluid is lower. Proteins trap sodium ions in the cytoplasm and pump them out from the cells to preserve cell stability while preserving concentrations. Within the cells proteins inject potassium ions into the cell.
Answer:
The primary reason is that the pollen grains are being struck by water molecules that move in different directions. These strikes fluctuate and sometimes are uneven.
Explanation:
This vibration and spread out of molecules in water is called Brownian Motion. It is the result of the collision of small particles of water with big particles of pollen. As the particles of water move randomly hitting different sides of the pollen particle, at times, there will not be a coordinated movement, but as the movement of water particles is random, there will be moments when one side of the pollen particle will collide with more water particles, when this happens there is an unbalanced force that makes the pollen particle moves in a direction.
