In prokaryotic cells, regulator proteins bind to a section of DNA called a/an A)chromatin
B)repressor***
C)promoter
D)operon
“*** is my answer”

C) Promoter

Explanation:

Gene expression is the process of synthesizing RNA from a gene (transcription), and subsequently, proteins from mRNA (translation). In both prokaryotic and eukaryotic cells, gene expression is controlled at the transcriptional level, which is regulated by certain proteins called transcription factors. Transcription factors are proteins that regulate the synthesis of a protein from a gene.

Transcription factors regulate the progression of transcriptional process by binding to a regulatory region on the DNA sequence about to be transcribed called PROMOTER. The promoter region is a DNA sequence contained in the OPERON. This binding influences the binding of the transcription enzyme, RNA polymerase in order for transcription to start.

the correct answer is option b

behavioral response need communication and thus co-ordination at several levels such as interaction among cells, organ system and the entire organism.

behavioral response produces both internal and environmental stimulus.

the corpus luteum secretes estrogens and progesterone. the latter hormone causes changes in the uterus that make it more suitable for implantation of the fertilized ovum and the nourishment of the embryo. if the egg is not fertilized, the corpus luteum becomes inactive after 10–14 days, and menstruation occurs.

i hope this : )