The correct answer is: D) secretin
Gastric secretion is highly regulated whether its secretion should be increased (when food is eaten) or decresed (as the stomach empties). Secretion is controlled by the nervous system and endocrine system that work together. There are three phases of gastric secretory control:
Cephalic-by the brain
Gastric-by the stomach itself
Intestinal- by the small intestine
All of three can work simultaneously.
Secretin is released by duodenal enteroendocrine cells and it stimulates the pancreas and gall bladder, but also suppresss gastric secretion and motility. Secretion of the secretin is stimulated by the chime and it is the part of intestinal phase.
In geology, a key bed (syn marker bed) is a relatively thin layer of sedimentary
rock that is readily recognized on the basis of either its distinct
physical characteristics or fossil content and can be mapped over a very
large geographic area.[1]
As a result, a key bed is useful for correlating sequences of
sedimentary rocks over a large area. Typically, key beds were created as
the result of either instantaneous events or (geologically speaking)
very short episodes of the widespread deposition of a specific types of sediment. As the result, key beds often can be used for both mapping and correlating sedimentary rocks and dating them. Volcanic ash beds ( and bentonite beds) and impact spherule beds, and specific megaturbidites
are types of key beds created by instantaneous events. The widespread
accumulation of distinctive sediments over a geologically short period
of time have created key beds in the form of peat beds, coal beds, shell beds, marine bands, black in cyclothems, and oil shales. A well-known example of a key bed is the global layer of iridium-rich impact ejecta that marks the Cretaceous–Paleogene boundary (K–T boundary). Please let me know if it works.
gamete: a mature haploid male or female germ cell which is able to unite with another of the opposite sex in sexual reproduction to form a zygote.
spore:a minutes typically one-felled, reproductive unit capable of giving rise to a new individual without sexual fusion, characteristic of lower plants, fungi, and protozoans.
algae: a simple, nonflowering, and typically aquatic plants of a large group that includes the seaweeds and many single-celled forms. algae contains chlorophyll but lack true stems, roots, leaves, and vascular tissue.
fungi:any group of spore-producing organisms feeding on organic matter, including molds, yeast, mushrooms, and toadstools.
lichen:a simple slow-growing plant that typically forms a low-crusty,leaflike, or branching growth on rocks, walls, and trees.
decomposer: an organism, especially a soil bacterium, fungus, or invertebrate, that decomposes organic material.
The similarity of 94% in their DNA sequence suggest that they have originated from a common ancestor and are closely related species.
Explanation:
The difference in DNA sequences in different species is due to the accumulation of genetic variation in the course of natural selection and evolution. Less is the difference in DNA sequences of two organisms the more related they are.
Genes determine the characteristics in an organism, and they are DNA sequences determining the protein to be formed. The similarity in DNA sequence of two species establish the evolutionary relationship among them.
Due to the genetic variation in species, the natural selection of the species had caused the evolution of the species adapted well to the environment.
