Plant cells have cell walls and animal cells do not because the plant cell needs it for its activities.
Cancer is an abnormal and uncontrolled multiplication of cells.
<span>Cancer also involves abnormal cell growth with the potential to spread to other parts of the body via blood and to form metastasis. Cancer cells avoid apoptosis (programmed cell death), have the limitless number of cell divisions and promote blood vessel construction. There are more than 100 types of cancers that affect humans with different signs and symptoms and with many different causes. </span>