Why is HIV called a retrovirus?

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.

When you aware sick your body produces more leukocytes.briefly describe where the leukocyte are formed,how they are transported,and where they may be stored.

The passing on of genetic traits from parents to offspring.