The atlantic salmon lives in the ocean for most of its life. every year, it returns to freshwater rivers to spawn. based on what you’ve learned so far about membrane proteins, diffusion, and osmosis, what kind of mechanism allows the salmon cells to adapt to freshwater after leaving saltwater?

The correct answer would be osmosis.

Explanation:

When salmon are in freshwater, they are in the hypertonic condition to their surroundings because of more water outside the body cells than inside. The water moves inside the body cells due to osmosis.

So the salmon suffer from water lodging and low salt in the body. It detected by the hypothalamus and regulate pituitary for secreting the hormone. The hormone results in the transport of ions to occur within the gill cells while they absorb salts across the gill cells which ultimately exchange sodium and chlorine ions against the concentration gradients.

Thus, the correct answer would be osmosis.

the level of progesterone is low at the pre-ovulatory phase of the cycle but it gradually increases and the levels are high at the luteal phase. if pregnancy occurs, the level of progesterone will be high throughout the pregnancy.

if egg is fertilized and the mother gets pregnant, progesterone starts preparing the uterus for the implantation. it starts building up the lining of uterus and make it hostile of the period of pregnancy.