C. because stimuli is how your body responds to something, and in this case, someone's heart rate increases WHEN their blood oxygen drop. Do you see how it responds? ;-)
Answer - C. Bodies of water would freeze from the bottom up.
Reason - Since solid water aka ICE is denser than liquid.. Then we can kiss our penguins good buy cause the whole Earth will be submerge of water since the Arctic is made of ice and if it sank boom there goes for the planet and so as Antarctica.
Answer: C. Their camera
Toolmarks are the impressions left by an object or tool on it's contact surface. Toolmarks are searched and collected in a crime scene to relate a link with the tool which has created them. In crime scene investigation, toolmarks found in the scene of crime should be photographed by the analyst in close range, mid range and overview range shots in order to record it's original location, shape, size and number if multiple tool marks are present.
80 chromosomes (40 pairs)