What is the part of the cell cycle process by which chromosomes in a cell nucleus or separated into two identical sets of chromosomes each in its own nucleus

This aquarium exhibits biotic and abiotic factors in an aquatic environment. one of the abiotic factors is

Look at the following answer choices and determine which belongs in the both category. testable, can be disproven explains natural phenomena, has evidence to support it prediction, tentative, one or more scientists working together well established, many different scientists working independently, highly reliable

Surrounded by microtubules, located near the nucleus. (don't try to google it) (give answer only if u know)