At first, it was thought that the Earth's atmosphere consisted of hydrogen compounds—methane, ammonia and water vapour—and that life began under such reducing conditions, which are conducive to the formation of organic molecules
Answer:
D
Stage 1 is an adult plant, stage 2 is a sprout
Answer:
C. Platelet adhesion
Explanation:
Platelet adhesion comes first in the process of hemostasis.
The process of hemostasis has got three phases:
- Vascular spasm
- Platelet plug formation
- Blood coagulation
The process occurs in the body in the event of a bleeding injury.
In the first phase, damaged blood vessels constrict to prevent more bleeding.
In the second phase, platelets adhere to damaged endothelium to form platelet plug.
In the third phase, fibrinogen is converted to fibrin to form a clot.
Answer:
C) Both are waves of energy, but ultraviolet waves cannot be seen.
Explanation:
Both visible light and ultraviolet are two manifestations of the same thing: electromagnetic radiation (which is, basically, energy in one of its forms). They both travel empty space as waves, but visible light has a longer wavelength, which means that the distance between succesive peaks of the wave is larger than that of ultraviolet radiation. Visible light just happens to have a wavelength in the range our eyes are capable of seeing, but ultraviolet has a shorter wavelength than that, therefore we cannot see it.
The question is incomplete. The complete question is:
Plasmodesmata are cell junctions that are found between ________.
a) adjacent animal cells in the same tissue type
b) individual cardiac cells in heart muscle tissue
c) the plasma membrane of actively dividing prokaryotes
d) adjacent plant cells
Answer:
d) adjacent plant cells
Explanation:
Plasmodesmata are the cytoplasmic channels that connect the adjacent plant cells together and maintain the continuity of their cytoplasm. These are the narrow channels with 20-40 nm diameter. Plasmodesmata serve the function analogous to the gap junctions of the animal cells. The presence of plasmodesmata between the neighboring plant cells allows the movement of molecules and ions between them. Plant cells can adjust the diameter of the plasmodesmata according to the requirement to allow the transport of substances across them.
