What is the primary source of energy for most ecosystems

Which of the following is a main difference in cell structure between an onion cell and a human cheek cell? a. an onion cell contains one nucleus, whereas a human cheek cell contains two nuclei. b. an onion cell has a cell wall. c. a human cheek cell contains chloroplasts. d. there is no difference between an onion cell and a human cheek cell. you for your.

Which best describes the digestive system of arthropods? a incomplete, two openings b complete, one opening c two-way, one opening d one-way, two openings

Will mark branliest. the theory of plate tectonics was developed with the contribution of scientists from many different disciplines. which of the following is a contribution from geophysicists?