Increase of earth's average temperature
The greenhouse effect occurs when rays enter our atmosphere and are reflected from the ground up. They get changed during their voyage through our atmosphere and they change in such a way that they can't leave the atmosphere anymore. Then they stay inside and heat up the planet which causes thing like global warming. That's what the greenhouse effect is.
Answer: c) and b) are correct.
The brain is encased in a protective bony or cartilaginous housing in craniates.
The anterior end of the nerve cord is elaborated to form a brain in craniates.
Explanation: The craniates include the chordata with well-defined heads. This includes mammals, reptiles and fishes. So we can discard the other answers. Because most craniates have functional jaws, and the adults do not lose their chordate characteristics. The last one does not apply as a specific feature because the tunicate have neural crest but are not recognized as craniata.
There should not be any changes in the gene pool.
In Hardy-Weinberg equilibrium, the gene pool should have a constant rate. The equilibrium can be achieved if there is no factor that favors one gene more than the others. Since the genes have the equal chance to survive and mating, the ratio of the gene pool should not change dramatically.
