Which of the following characteristics of eukaryotic cells is used to support the theory that they evolved from the union of free-living cells? A. The ability to transport materials across a membrane
B. The presence of mitochondrial DNA
C. Reproduction by mitotic cell division
D. Differentiation of stem cells into specialized cells

The following image is of a diatom. it lives in water and gets food from photosynthesis. it is encased in a hard shell made of something similar to glass or sand . a diatom is a(n) because it has a) multi-celled organism; specialized parts. b) vertebrate; a skeleton. c) insect; an exoskeleton. d) single-called organism; only one cell.

World class speed skaters can skate a 3,000-m course in about 4 minutes. what is their average speed for this course. a. 12.5m/s b. 1.33m/s c. 13.3m/s d. 1.25m/s

Which of the following is not a food produced in rainforests? a) coffee b) cocoa c) avocados d) wheat