Ecosystems can be changed by natural events or by human actions. which is not a natural event? a. a forest fire started by lightning b. pollution from a factory entering a river c. a beaver building a dam in a river d. an earthquake

Hi! The answer would be B. pollution from a factory entering a river because humans built the factory so that it would drain into the river, therefore it is unnatural.

What is the difference between cytokinesis in plant and animal cells? animal cells dived by a cleavage furrow. plant cells divide by a cell plate that eventually becomes the cell wall. cytoplasm and cell membranes are necessary for cytokinesis in both plant and animals.