Which of the following is not property of optical telescopes<span>. Refracting power or Reflecting power</span>
True
Phloem is used for the transport of minerals
Xylem is used for the transport of water
Answer:
A. COAGULATION
Explanation:
Hemostasis is stopping bleeding. To prevent or keep blood in the blood vessels due to damage of the vessels.
Three steps are important in hemostasis;
1. Vasoconstriction : which is the contraction of the smooth muscles of the blood vessels reducing the amount of blood flow to the area of damage and thereby blood loss.
2. Platelet Plug Formation: this is the function of platelet in the blood. It attaches to the damaged endothelium and form a plug.
3. Coagulation/ Clotting : this is the release of clotting factors to the surface of the damaged vessel.
Fibrin is a major component of the clotting factor.
So therefore, coagulation is a process in hemostasis. Formation of platelet plug is a stage also and not the formation of platelet in the blood.
The right answer is The pressure in veins is lower than in arteries, causing less seepage of blood.
The arteries are the vessels located at the exit of the heart towards the organs. When the heart contracts like a pump to expel the blood to the arteries, the pressure is very strong. This is called systolic pressure. To cope with this pressure, the arteries have a thick and elastic wall, to be able to stretch without breaking. The arteries have an average diameter of 2.5 centimeters, against less than 2 mm for arterioles.
Unlike the arteries, the veins are subjected to a weak pressure, since the blood starts from the organs and not from the heart. The walls of the veins are therefore thin and fairly rigid because they have little resistance to provide against the pressure. The diameter of the veins and venules is rather small (smaller than arteries) and hardly varies. Veins and venules contain about 75% of the blood. During a cut, the blood of the veins gradually trickles.
So from these explanations, we can conclude that the propositions B; C and D are false, it is rather their opposite that is right.