First, he should measure how long it takes for the liquid to become clear if X and Y are mixed together. Then, he should measure how long it takes if he also adds substance A to X and Y. He will find out if substance A is a catalyst.
Answer:
A) Calcitonin injection
Explanation:
Parafollicular cells or C-cells of the thyroid gland produce a hormone which is involved in the regulation of calcium levels in the blood. This hormone is Calcitonin. It works in an antagonistic manner with the Parathyroid hormone (PTH). Calcitonin decreases the calcium level in the blood by increasing absorption of calcium ions in bones. In osteoporosis, when the patient is given the injection of hormone calcitonin, it produces and increase in bone mass because it negatively affects the rate of absorption of bone by the osteoclasts.
Because during digestion, blood is needed to execute the process.
Swimming also requires blood so it takes the blood that was initially being used for digestion away.
Hope it helped!
Prokaryotes do not contain membrane, and eukaryotes do contain membrane.
