The answer is e. Calcitonin, Aldosterone and Atrial natriuretic peptide.
The calcitonin is a hormone secreted by the thyroid gland. Calcitonin is involved in the regulation of the levels of calcium and phosphate in the blood. Aldosterone is a hormone secreted by the adrenal gland. It is essential for maintaining the store of sodium in the kidney, salivary glands, sweat glands and colon. Atrial natriuretic peptide (ANP) or Atrial natriuretic factor (ANF) is a peptide hormone synthesized, and secreted by cardiac muscle cells in the heart. ANP is involved in the regulation of sodium levels in the cells of the heart.
The correct answer is - D) covered by warm shallow seas.
The fact that the crinoids are have an abundance in the fossil records in Pennsylvania in the Mississippian Period, tells us that this area was covered with shallow and warm seas. The reason why we can get that conclusion is that the crinoids live only in that kind of environment, so it simply a logical conclusion.
The geological data is also confirming this, as it is easily noticeable in the layers that during this period of the geologic past, what is now Pennsylvania, was covered with shallow sea waters. Also, this waters were warm too, as the climate was warm and humid and that period, so it was a perfect environment for the crinoids to flourish.
Spirogyra<span> is a genus of filamentous charophyte green algae of the order Zygnematales, named for the helical or spiral arrangement of the chloroplasts that is diagnostic of the genus.
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