The following graphic represents the control of calcium ion levels in the blood: The figure portrays the regulation of calcium ions in the blood. Low blood concentrations of calcium ions stimulate the parathyroid gland to increase secretion of PTH, which acts on the kidney, large intestine, and bone to increase blood calcium levels. Once high levels of blood calcium are reached, the thyroid gland is stimulated to secrete calcitonin, which stimulates the bone and kidneys to decrease blood calcium levels. Concurrently, the high blood levels of calcium inhibit the parathyroid, which decreases PTH secretion, which lowers blood calcium levels. Which statement is true if PTH is removed from the system upon secretion, resulting in negative feedback

Which of the following is an advantage of solar energy?

Consider the motion of the balloon and its air contents in terms of momentum. in step 1 above, the total momentum of the balloon and its contents was zero. recall that momentum = mv. both the balloon and the air inside it had a velocity of zero and therefore the total momentum was zero. now think about what happened when the air escaped from the balloon. a certain mass of air accelerated in one direction. in order to keep the total momentum of the system zero, the balloon itself (which has mass) had to accelerate in the opposite direction. use this scenario to you explain why the soda can rotates when the water squirts out of the escape holes. what was your hypothesis concerning the water-filled can? according to your data, do you think your hypothesis was correct? (be sure to refer to your data when answering this question.) summarize any difficulties or problems you had in performing the experiment that might have affected the results. describe how you might change the procedure to avoid these problems. give at least one more example of newton's third law in everyday life.

In 2001, records showed that local stocks of fish were down worldwide. yet, records of harvests indicated that fish were being taken at records rates. what was actually happening?