Which statement best describes cancer cells? They grow as a single layer of cells.
They cease to reproduce after 20–50 mitotic divisions.
They reproduce only when needed to replace missing cells.
They are not regulated by contact inhibition.

They are not regulated by contact inhibition.

Explanation:

Contact inhibition is a form of controlling cells. Cancer doesn't have contact inhibition, which is one of the reasons why it spirals out of place so easily.

the answer to your question is b

a

explanation:

many plants naturally reproduce this way, but it can also be induced artificially. horticulturalists have developed asexual propagation techniques that use vegetative plant parts to replicate plants. success rates and difficulty of propagation vary greatly. monocotyledons typically lack a vascular cambium and therefore are harder to propagate.