I believe it is A because I know Nonpoint source pollution can include excess fertilizers, herbicides and insecticides from
Agricultural lands and residential areas. I hope it is right.. please let me know
The answer is B - Archea, Bacteria, and Eukarya are all Domains
Answer:
Tryptophan synthesis enzymes be made during low level of cellular tryptophan.
Explanation:
Tryptophan operon contain 3 regulatory gene(trpR,trpP and trpO) and 5 structural genes(trpE,trpD,trpC,trpB and trpA) .trpR encodes the repressor protein that interacts with tryptophan present in the media and then the tryptophan repressor complex binds to the operator region to block the transcription of the structural genes of tryptophan operon.
Here tryptophan acting as a corepresor.During mutation of trpR gene tryptophan biosynthesis enzymes will be synthesized only when the cellular tryptophan level remains very low.
That is not unusual. The nursing mother’s breast may be engorged and full of milk, but it won’t come out of the nipple. Milk production and nursing is not a simple process. Once the breasts are full of milk, another mechanism ejects the milk out of the nipple. Continuous sucking on the nipple stimulates the hypothalamus of the brain (yeah, it goes up from there), which secretes oxytocin that contracts the cells blocking the milk ducts, allowing milk to come out of the nipple. If milk won’t come out, the patient might have deficiency in oxytocin. In that case, try having the newborn continuously suck on the breast for few minutes.
