<h2>
Reproductive Method </h2>
Explanation:
<em>The rank in order from the most specific which is following .</em>
<em>(1) Reproductive isolating mechanism</em>
<em>(2) Sperm-egg incompatibility in sea urchins</em>
<em>(3) Gametic isolation </em>
<em>(4)Prezygotic isolating mechanism</em>
<em>(1) Reproductive isolating mechanism-</em> The components of regenerative confinement are an assortment of transformative instruments, practices and <em>physiological procedures basic for speciation.</em> They keep individuals from various species from delivering posterity, or guarantee that any posterity are sterile.
(<em>2) Sperm-egg contradiction in ocean urchins-</em> Bindin is a gamete acknowledgment protein known to control species-explicit <em>sperm-egg grip</em> and layer combination in ocean urchins.
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(3)Gametic isolation - Prezygotic hindrances </em>keep preparation from occurring. Gametic disengagement is a sort of prezygotic hindrance where the<em> gametes (egg and sperm) </em>come into contact, yet no preparation happens. Gametes might be not able to remember each other in various species
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(4) Prezygotic isolating mechanism- </em>while postzygotic segregation forestalls the arrangement of rich posterity. Prezygotic systems incorporate environment segregation, mating seasons, "mechanical" disconnection, gamete detachment and conduct seclusion.
Sources of heat from inside earth is radioactive decay and residual heat.
Consists of cranial and spinal nerves carrying impulses to and from the brain and spinal cord
The correct answer is B, I know this because none of the other answers are even reasonable. For example-
A is wrong because the size of elephant tusk has not changed over time, elephant tusk just grow...
C is wrong because it makes no sense to hunt elephants with no tusk :/
D is completely wrong because tusk have nothing to do with reproduction, those are two completely separate bodily functions.........
Some species cell division produces reproductive cells in sexually reproduce organisms