The answer is an envelope.
A virus is an infectious agent that can replicate only inside a host cell. When it is outside the cell, it consists of genetic material coated with protein capsid. Some viruses also have an envelope which covers capsid. The function of the envelope is to identify and bind some receptor sites on the host membranes. After fusing with the cell membrane, it allows to capsid and genetic material to enter the cell and infect it.
Answer:
1. C. environmental scientists
Explanation:
Environmental scientists serve on matters like the perception of surface methods, assessing alternative energy methods, pollution control and moderation, natural source administration, and the consequences of global atmosphere difference. Environmental issues most ever involve an interaction of environmental, biochemical, and life methods. Environmental specialists bring a methods suggestion to the judgment of environmental obstacles. Key components of an efficient environmental expert involve the capacity to associate space, and time associations as well as quantitative study.
2. A
3. B
I think the best answer is D. It is thought that advances such as agriculture, literacy, and urbanization have not been accompanied by additional increases in brain size because the physiological cost of a bigger brain exceeds its benefit. The brain requires a lot of nutrients to function. Having a bigger brain would cost a lot rather than benefiting from it.
2. Endothermic, absorbing
Hope this helps :)
Rickets is the disease in children in which an inefficient mineralization of the bone forming tissue causes deformities. This condition results in weak or soft bones in children, normally due to an extreme and prolonged deficiency of vitamin D. Vitamin D promotes the absorption of calcium and phosphorus from the gastrointestinal tract. The symptoms include bowed legs, stunted growth, bone pain, large forehead, and trouble sleeping among others.
