Nutrients move through the ecosystem<span> in biogeochemical </span>cycles<span>. A biogeochemical </span>cycle<span> is a circuit/pathway by which a </span>chemical<span> element moves through the biotic and the abiotic factors of an</span>ecosystem<span>. It is inclusive of the biotic factors, or living organisms, rocks, air, water, and </span>chemicals<span>.</span>
Complete Question:
Which of the following might stimulate the cephalic phase of gastric secretion?
A. stomach distention
B. the production of saliva
C. the thought of food
D. the production and secretion of gastrin.
Answer:
C. the thought of food
Explanation:
Gastric secretion usually occurs in three different phases, namely;
- Cephalic
- Gastric
- Intestinal
The thought of food usually stimulate the cephalic phase of gastric secretion in organisms. The presence of lipids or low pH inhibits Gastric secretion during the intestinal phase.
Yes. True vertebrates have a true head that develops from a neural crest of cells and hard structures surrounding the notochord.
The neural crest, which forms early in the development process in vertebrate embryos, is a fold on the neural plate where the neural and epidermal ectoderms converge. As an embryo grows, the neural crest produces neural crest cells (NCCs), which can differentiate into a variety of different cell types and contribute to tissues and organs.
The notochord is a temporary structure that plays a crucial role in higher animals. It secretes substances that communicate with all neighbouring tissues, telling them where they are and what will happen to them.
Therefore, True vertebrates have a true head that develops from a neural crest of cells and hard structures surrounding the notochord.
Learn more about notochord here:
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Erythropoiesis is the formation of the red blood cells a process which takes place in the bone marrow. All blood cells are formed in the bone marrow, a soft, highly cellular tissue that fills the internal cavities of the long bones. It takes place in 8 stages where the first seven steps takes place within the bone marrow and after the 7th step the red blood cell is released into the blood stream as reticulocyte which then matures to erythrocyte after 1-2 days.