How do some cells become brain cells and others become skin cells, when the DNA in all the cells is exactly the same?

The kind of fertilization found in the majority of aquatic animals is (internal or external) fertilization.

Which of the following statements is most likely correct about a rock belonging to the jurassic age and a rock belonging to the cambrian age? options: 1) they have identical fossils of organisms that have evolved over time. 2) both have animal fossils preserved in them due to weathering and erosion. 3) they contain different fossils because life on earth has changed through time. 4) the fossils in them were formed on the surface of earth due to exposure to sunlight.

Which is an example of a vestigial structure? a. tail of a monkey b. fin of a fish c. flower of a plant d. tailbone of a human