A virus is a microscopic particle that can infect the cells of a biological organism. Viruses can only replicate themselves by infecting a host cell and therefore cannot reproduce on their own. It has been argued extensively whether viruses are living organisms.
Nucleic acid is the macromolecule that carries code for building our body.
Biology is the study of living thing
<span>Opaca and Marginal zone stays outer and does not move during chick gastrulation,
The zone opaca is a thick fringe ring comprising of more than one cell, it is joined to the germ wall. The Marginal zone lies at the fringe between the range opaca and the region pellucida</span>
