Which pair of chromosomes can contain two very different chromosomes and still be considered normal?

What is the phylum of soft bodied animals with a true bosy cavity and a three part body consisting of a foot visceral mass and a mantle

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.

List five ways we are indebted to phytoplankton