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.
Biomass is plant or animal material used as fuel to produce electricity or heat. Therefore i think the answer is plants!
<span>Plants use carbon dioxide and sunlight to make their own food and grow the carbon becomes part of the plant. Plants that die and are buried may turn into fossil fuels made of carbon like coal and oil over millions of years. When humans burn fossil fuels most of the carbon quickly enters the atmosphere as carbon dioxide :) i love biology</span>
