Answer:
It's important for a scientist to try to hold all variables constant except for the independent variable. If a control variable changes during an experiment, it may invalidate the correlation between the dependent and independent variable. When possible, control variables should be identified, measured, and recorded.
Function of integumentary system: PROTECTION<span>- barrier against infectious, chemical, radioactive, and physical damage.
- keratin and junctions block bacteria, fungi, and blunt objects.
-macrophages identify foreign particles and activate immune response.</span>
Centromeres split apart during anaphase.
spindle fibers pull the to sister chromatids apart.