How old is the earth? what study is the basis for all geologic time periods ?

What are some characteristics of a free enterprise economy?

What best describes the dropping height of a ball that bounces back up to a height of 45 cm

How do you know that the plant cells in these two images have different jobs, or functions? a. because all plant cells serve different functions b. because they are two different colors c. because their dna are different d. because their structures are different