Answer:
Plants must have evolved in a manner where they require less water and nutrients as these two were the only limiting factor and carbon dioxide was in abundance
Explanation:
Some 400,000 years ago, the concentration of CO2 was very high and was near to 1000 ppm. At this high concentration of CO2 the photosynthetic activity of plants becomes very high and thus since 400,000 years ago plants could have evolved in an uncontrolled manner but this does not happened. So the reason behind this is limitation in terms of soil and its constituent’s nutrients availability and also limited supply of water.
Therefore, if plants would have evolved themselves in a manner where they require less water and nutrients then they would have grown limitless.
Answer:
La Tierra primitiva no tenía una atmósfera o agua libre. El planeta estaba demasiado caliente para que los gases y el agua se acumularan.
Explanation:
Answer:
The radii of the arterioles constrict by humoral control and by nervous control.
Explanation:
The vascular system regulation is performed by the smooth muscle of the arterioles, which constitute the maximum resistance point. The smooth muscle relaxation provokes vasodilation, increasing its diameter. On the contrary, smooth muscle contraction provokes a decrease in the arteriole´s diameter, reducing the blood flow.
This muscle is under the control of the autonomous nervous system and certain hormones.
Substances such as adrenaline, noradrelanine, angiotensine, vasopresin, and endotelines cause vasoconstriction.
Also, there are many vasoconstrictor fibers of the sympathetic nerves that increase resistance and modify blood flow.
I think it is 40 percent, that is what fao(.org) says
A particle because it's a particle
