Is a zygote the first cell of a new organism?

Multicellular organisms use cell division, mitosis, for growth and the maintenance and repair of cells and tissues. single-celled organisms may use cell division as their method of reproduction. regardless of the reason for mitosis, the process ensures genetic continuity. what is the step in the cell cycle that ensure genetic continuity?

Why do we perceive objects as retaining their brightness under different lighting levels?

Suppose you use three different scale to weigh a bag of organges. one scale says the nag weighs 2.1 lb, and third says it weighs 2.1 lb. the actual weight of the bag of organges is 2.153 lb. which of the following best decribes these results?