Answer:
Answer is B.
Explanation:
<u>Period is duration of time</u>.
Period can be of a second,minute,hour or of Some years.We will give unit according to the duration of time.In the given options second is most obvious because it is used to measure time.
I think one major difference with that is that animals can move around, go distances in search for food or mate, and thus make the animal densities per geography vary greatly. Birds migrate regularly, so their population densities tend to vary with seasons. Their mobility also depends on the availability of food, so animals go away if there are no food in the area.
Plants on the other hand don't move around faster (they can migrate by reproduction: it's their seeds moving around). Thus their densities tend to be more constant per season/life cycle.
Answer:
<u>Luteinizing hormone </u>(LH) stimulates Leydig cells to secrete testosterone
<u>Follicle stimulating hormone (FSH)</u> stimulates Sertoli cells to secrete protein and other molecules required for spermatogenesis
Explanation:
Under the influence of gonadotropin-releasing hormone, the anterior pituitary releases luteinizing hormone (LH) and follicle-stimulating hormone (FSH). In males, LH stimulates interstitial cells of testes (Leydig cell) to secrete the hormone testosterone. FSH acts indirectly to stimulate spermatogenesis by causing the release of androgen-binding protein (ABP) from the Sertoli cells. The function of ABP is to maintain the higher concentrations of testosterone to stimulate the final steps of spermatogenesis in the seminiferous tubules.
The arctic environment is deathly cold, hence the thick blubber on animals so they can handle freezing temperatures
