Mature mammalian red blood cells lack nuclei, mitochondria and rough endoplasmic reticulum, they do not contain DNA and consequently, cannot divide. They also cannot synthesise RNA nor synthesise any new proteins, and consequently, have a limited lifespan. Mature red blood cells circulate for about 100–120 days in the body before they are removed by the spleen.
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Physical science deals with lens for cameras and binoculars.
Explanation:
Physical science is a branch of science that deals with the study of intimate natural objects such as it includes physics, astronomy and chemistry related subjects.
A lens is a transparent material that refracts light rays so that image can be formed. A lens has two curved surface which are made up of plastic or glasses which are concave and convex in nature. A converging lens is used to produce images.
Thus Nancy is dealing with physical science as she designs lens for binoculars and cameras.
<u>Answer</u>: A) Africa and South America only
As shown in the map, the fossil evidence suggests that Cynognathus lived on the modern day continents of South America and Africa. Thus, from this distribution and the fragmentation of the ancient landmass into today's continents, result in the distribution of Cynognathus offspring species also only within the continents of Africa and South America.
The correct option is B.
The field of science is very dynamic and it thrives on discovery of new evidences. When new evidence are found for a particular phenomenon, the existing phenomenon has to be adjusted to fit the new discovery. Air pollution was once named to be responsible for global cooling because enough evidence was not available then to prove otherwise but now overwhelming evidences show that pollution is responsible for global warming.<span />
