During a period of time outside the host, a virus may become and lose many factors that are required for infections. these viruses stimulate the immune system with much lower mortality than the fully virulent strains.

What is the difference between cytokinesis in plant and animal cells? animal cells dived by a cleavage furrow. plant cells divide by a cell plate that eventually becomes the cell wall. cytoplasm and cell membranes are necessary for cytokinesis in both plant and animals.

Centriole.centrioles are present in animal cells but are usually absent in plant cells.