1.
a. deoxyribose sugar, phosphate, and nitrogen-containing base
b. deoxyribose sugar
c. cytosine
d. adenine, thymine, guanine. and cytosine
The explanations of natural phenomena, and additional hypothesis most often come about as a result of a scientific theory.
Explanation:
Scientific theory is a general explanation of natural phenomena developed through extensive and reproducible observations, more general and reliable than a hypothesis.
Then Every scientific theory starts as a hypothesis. A scientific hypothesis is a solution for an unexplained occurrence that does not fit into a currently accepted scientific theory. It must be based on careful rational examination of the facts.
Answer:
Calcium
Explanation:
Parathyroid hormone (PTH) is a hormone that is secreted by the parathyroid gland. It is the major regulator of the plasma concentration of calcium ions. It regulates calcium ions in the kidney, intestine and bones.
In the kidney, is involved in the re-absorption of calcium in distal ducts and the renal collecting duct, it is also involved in activating the conversion of 25-hydroxy vitamin D into 1,25-dihydroxy vitamin D (calcitriol).
In the intestine, PTH is involved in the absorption of calcium, by increasing vitamin D production.
In the bone, it helps in regulating calcium levels; when serum calcium level is low, PTH stimulates the activity of the osteoclast, to produce more calcium.
Answer:
Has a Dorsal hallow nerve cord, a notochord pharyngeal pouches, and a tail that extends beyond the anus.
Explanation:
I believe a river is the answer
