Answer:
c. Glycolysis evolved in an oxygen-rich environment.
Explanation:
Glycolysis is the pathway that breaks down glucose into two molecules of pyruvate. It is a common pathway that is performed by both aerobic and anaerobic organisms. In aerobic organisms, glycolysis is followed by Kreb's cycle and electron transport chain. In anaerobic organisms, alcohol or lactic acid fermentation regenerate the NAD+ which is required to sustain glycolysis.
Therefore, glycolysis is independent of oxygen availability and can be performed under both aerobic and anaerobic conditions. This means that the pathway of glycolysis evolved under anaerobic conditions.
Both men and women have sex chromosomes. Men usually have one X and one Y chromosome, while women have two X's.
When an egg or sperm is made, it only gets one of the sex chromosomes from the parent. This means that women can only make eggs with an X chromosome. But men can make either X or Y sperm.
During fertilization, the sperm cells race toward the mother-to-be's egg cell. If a sperm with a Y beats all others, then the fetus will be XY. The pregnancy will result in a boy.
However, if a sperm with an X wins the race to the egg, then the fetus will be XX. The parents will have a baby girl.
Nearly everyone's chances are around 50% for having a boy and 50% for having a girl. And yet, we all know families that are all boys or all girls.
Answer:
regulation of the diameter of blood vessels and control of blood pressure
Explanation:
Skeletal muscles are the multinucleated muscles with striations and are attached to the bones (skeleton). The main function of skeletal muscles is to generate the voluntary movement of the body or body parts. The skeletal muscles of face, rectum, and urinary bladder generate their voluntary movement as per the will of the organism. On the other hand, blood vessels are lined with smooth muscles with spindle-shaped cells.
For example, the muscles present in the subcutaneous layer of the skin of the face are responsible for various facial expressions. Contraction of these facial muscles brings about the movement of skin of the face to generate a wide variety of emotions. Smooth muscles of blood vessels are involuntary in nature.
Vasodilation and vasoconstriction as brought about by smooth muscles of blood vessels are regulated by the autonomic nervous system. Under the conditions of lower blood pressure, contraction of smooth muscles of blood vessels restore the reduced blood pressure. On the other hand, when the blood pressure rises above the normal range, the smooth muscles of blood vessels relax to dilate them and to lower down the blood pressure.
