What is a nucleus, chromosome, chlooplasts,cell membrane, cytoplasm?
controls what goes in and out of the cell
holds all the cell organelles
contains all the genetic info in a cell
fluid filled bubble responsible for getting rid of waste
in plant cells, converts energy from the sun into glucose
directs all of the cell activities

nucleus: directs

chromosome: genetic

chloroplasts: convert energy from sun

cell membrane: controls

cytoplasm: holds

Option D

Explanation:

The small pox virus would not be a good choice for a vaccine against cowpox. This is so because the intensity of the disease differs.

The small pox is more severe and its virus cannot be used in a attenuated form to generate immune response for small pox.

There are chances that doing so might kill the person with small pox as it has high fatality rate than cowpox. Even if its is cured it leaves marks and scars.

So, small pox virus cannot be used as a vaccine against cowpox.