The unit used to measure period is the

a. hertz
b. second
c. meter
d. millimeter

Answer is B.

Explanation:

Period is duration of time.

Period can be of a second,minute,hour or of Some years.We will give unit according to the duration of time.In the given options second is most obvious because it is used to measure time.

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.