Answer:
A solar eclipse can occur only when new moon occurs close to one of the points (known as nodes) where the Moon's orbit crosses the ecliptic. ... Therefore, the Moon's apparent size varies with its distance from the Earth, and it is this effect that leads to the difference between total and annular eclipses.
The natural rate of extinction as assumed by science is about 5 species per year. Currently scientists estimate we are losing species at 1000-10000 times that rate, with multiple species disappearing every day. A note on this idea is that the average extinction rate gives an unrealistic depiction of nature when we consider the catastrophic extinction events that ended the dinosaurs and shaped the ice age.
Severe anemia may trigger an adaptive conversion of yellow bone marrow to red bone marrow.
Anaemia is defined as the decrease or the reduction of the oxygen carrying content of the blood which are the red blood cells.
These red blood cells and other blood cells which include the white blood cells and the platelets are produced in the body by the bone marrows by a process called haemopoiesis.
The bone marrow is divided into two:
- yellow bone marrow and
- red bone marrow.
The red bone marrow is made up of stem cells which can be converted to red cells when the need arises while yellow bone marrow is made up of fat.
During health conditions such as anaemia, there is increase in the need of red blood cells by the body.
There is usually the conversation of yellow bone marrow to red bone marrow to compensate for the increased demand of red blood cells.
This conversation is called an adaptive conversation.
Therefore,Severe anemia may trigger an adaptive conversion of yellow bone marrow to red bone marrow.
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