Answer:
The correct answer is A. a rotating cloud of dust and gas.
Explanation:
Nebulae are regions of the interstellar medium (clouds) made up of gases (mainly hydrogen and helium) and dust. In other words, nebulae are concentrations of gas in which we find hydrogen, helium and stardust in greater quantities. They are structures that are actually very important for the universe, this because inside it is the place where stars are born, which arise due to the condensation and aggregation of matter. The nebular theory states that the Solar System reached the form current from a solar nebula (a gas cloud), more than 4.5 billion years ago. The large cloud of molecular gas was affected by a certain phenomenon that would have taken place in the vicinity. Like the explosion of a supernova or the passage of a star that would produce a strong gravitational impact. The result of this event made the matter agglomerate in different places. The high concentration of matter caused the nebula to collapse. Becoming a protostar, (bodies whose characteristic is to be surrounded by clouds and contain preplanetary matter inside), that is, gaseous matter in the outermost part and solid inward. At the core of this structure, the temperature is so dominant that nuclear reactions take place to compensate for the gravitational force. This leads to a hydrostatic equilibrium and the formation of a fundamental star: the Sun. The rest of the mass flattened, forming a protoplanetary disk where the protoplanets were being formed, which would evolve to become the current planets, their satellites and the others bodies of the solar system.
Carbon dioxide is generated in tissues as a byproduct of normal metabolism. It dissolves in blood plasma to form carbonic acid (H2CO3); red blood cell (RBC) carbonic anhydrase catalyzes this reaction. Carbonic acid then spontaneously dissociates to form bicarbonate (HCO3−) and a hydrogen ion (H+). In response to the decrease in intracellular <span>pCO2</span>, more CO2 passively diffuses into the cell.
Cell membranes are generally impermeable to charged ions (i.e. H+, HCO3− ) but RBCs are able to exchange bicarbonate for chloride using the anion exchanger protein Band 3. Thus, the rise in intracellular bicarbonate leads to bicarbonate export and chloride intake. The term "chloride shift" refers to this exchange. Consequently, chloride concentration is lower in systemic venous blood than in systemic arterial blood: high venous pCO2 leads to bicarbonate production in RBCs, which then leaves the RBC in exchange for chloride coming in.<span>[2]</span>
Answer:
An earthquake that isolates a population of rodents on a mountain from other populations of rodents
Explanation:
Physiological changes during pregnancy aid the adaptation of the cardiovascular system to the grown metabolic needs of the mother which enables adequate delivery of oxygenated blood to peripheral tissues and the fetus. In the postpartum period, the Hemodynamic parameters slowly return to its baseline values, but the full resolution may take in six months after giving birth. The blood volume also decreases by 10% within 3 days after giving birth. The hemoglobin level and the hematocrit will stabilize after 2 weeks. The systolic and diastolic pressure will stay the same from late pregnancy until 12 weeks postpartum. Within 2 weeks of postpartum, the systemic vascular resistance will increase by 30%
