C) the sun warms the ground.
Answer: B
Explanation:
Ammonia is so toxic that it can be transported and excreted only in large volumes of very dilute solution. As a result most terrestrial animals simply don't have access to sufficient water to routine excrete ammonia.
The main advantage of urea is its very low toxicity. Animals can transport urea in the circulatory system and store it safely in high concentrations. Also much less water is loss when a given quantity of nitrogen is excreted in a concentrated solution of urea than would be in a dilute solution of ammonia.
Division of body cells results in a greater variety of traits
D) no change in cardiac output, increased heart rate, decreased stroke volume occurs after blood donation
Explanation:
When a person donates blood, there is a slight loss of blood volume or hypovolemia. This triggers the baroreceptors of the blood; although does not trigger the osmoreceptor.
The baroreceptor responses are according to the arterial pressure which rises momentarily and results in increased sympathetic activity with decreased vagal activity.
These changes will lead to vasoconstriction, reduced stroke volume, increased heart rate or tachycardia which helps to maintain the cardiac output.
The soreness at the venepuncture site on the skin is due to bruising which is common after any needleprick. applying cold pack, elevating and resting the arm.
In order to compensate for the fluid volume loss and avoid dehydration, one must take plenty of fluids before and after blood donation.
