Migraines are frequent intense aches of the head of neck
that are not caused by another physical disorder. Severe pain may usually be
felt on either one side or both sides of the head. Pain usually is felt in the temples.
Migraine could last for hours or couple of days.
I think the correct answer from the choices listed above is the third option. The DNA is used as a molecular clock in the sense that the <span>percent of carbon in DNA is compared between parent and offspring. Hope this answers the question. Have a nice day.</span>
Answer: We have found fossils that share specific bony traits that are found only in all whales but absent in every other mammal group, indicating descent from a shared common ancestor with modern whales, and these fossils had legs fully adapted for walking on land, and fundamentally identical to those of older mammals that precede the shared common ancestor that these mammals share with whales.
This tells us that the shared common ancestor of whales and these mammals with legs almost certainly had legs themselves, and inherited those legs from their own older mammal ancestors.
Therefore, whales have ancestors in their lineage that walked on land with legs.
(We also have multiple fossils of ancient whales that had legs transitional in form between fully terrestrial walking legs and flippers adapted for swimming, and modern whales still possess a remnant hip bone buried deep in their bodies.)
The main function of the PNS is to connect the CNS to the limbs and organs. The PNS sends information to the CNS as quickly as possible.
I hope this helps :)
