Answer:
The cuticle is the hair's protective layer, the cortex forms the pigment of the hair, the health of the cortex depends on the cuticle protecting it while the medulla is the innermost of the hair.
Explanation:
The cuticle is the hair outermost layer, the cortex is the middle structure for strength while medulla is the inner most.
The answer is Permian-Triassic extinction.
The Permian-Triassic extinction was 252 million years ago. It is known as The Great Dying because about 95% of all species died out due to environmental changes (volcanic eruptions, dry climate, melting of ice sheets, etc). This is also the only event in which many insect species wiped out.
The disorder where the grandfather and the grandchild are affected is related with the X chromosome and is called Sex linked or X linked disorder.
<h3><u>Explanation:</u></h3>
All the sex linked disorders are recessive in character i.e the normal allele is dominant over the mutated allele. In females, there are 2 X chromosomes, so the mutated allele is only expressed when there are both the mutated alleles, else its masked by the dominant normal allele. But in males, there's only one X chromosome, so if a mutated allele is present, it's readily expressed.
If the Grandfather is diseased, then he must have that mutated allele in X chromosome. Through reproduction, its received by the mother, but she is normal because the other allele received from grandmother was normal. But mother has one of the X chromosomes with mutated allele, which is received by the grandson who again becomes diseased.
So the disorder must be X linked disorder
