Dysfunctional uterine bleeding (DUB) is caused by a. endometrial fibroid tumors. b. absent or diminished levels of progesterone. c. endometrial inflammation. d. reproductive tract malignancies.

b. absent or diminished levels of progesterone

Explanation:

Dysfunctional uterine bleeding refers to abnormal uterine bleeding that causes the endometrial line to shred off in an abnormal manner.

Fibroid tumor, endometrial  inflammation and malignancies are indirect causes of uterine bleeding but most common cause is the hormonal imbalance.

Progesterone is responsible for development and maintenance of endometrium so absent or diminished levels of progesterone is the cause of DUB.

answer; /// i do believe its (heredity); good luck

c.) polymerase chain reaction

- "unlike the original dna fingerprinting method, dna profiling does not use restriction enzymes to cut the dna. instead it uses the polymerase chain reaction (pcr)? to produce many copies of specific str sequences. pcr is an automated procedure that generates lots of copies of a specific sequence of dna."