<span>Phagocytosis and pincytosis </span>
Answer:
Double fertilization involves two sperm cells; one fertilizes the egg cell to form the zygote, while the other fuses with the two polar nuclei that form the endosperm. After fertilization, the fertilized ovule forms the seed while the tissues of the ovary become the fruit.
Answer:
Calcium
Explanation:
Parathyroid hormone (PTH) is a hormone that is secreted by the parathyroid gland. It is the major regulator of the plasma concentration of calcium ions. It regulates calcium ions in the kidney, intestine and bones.
In the kidney, is involved in the re-absorption of calcium in distal ducts and the renal collecting duct, it is also involved in activating the conversion of 25-hydroxy vitamin D into 1,25-dihydroxy vitamin D (calcitriol).
In the intestine, PTH is involved in the absorption of calcium, by increasing vitamin D production.
In the bone, it helps in regulating calcium levels; when serum calcium level is low, PTH stimulates the activity of the osteoclast, to produce more calcium.
Answer:
Hypothalamic-pituitary-adrenal axis (HPA axis)
Explanation:
- The three-stage process describing the physiological changes that take place in the body when it is under stress is known as general adaptation syndrome (GAS).
- The model describing the three-stage process was given by the scientist Hans Selye.
- According to this model, the responses in the body that occur during stress is regulated by the Hypothalamic-pituitary-adrenal axis (HPA axis) where the brain senses the stress and then the signals travel from the hypothalamus to the pituitary and finally the body releases cortisol from adrenal glands that contributes to the various changes.
Answer: I believe the correct answer is choice A. The chromosomes are duplicated.
