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.

1: most common garden plants prefer loam — soils with a balance of different-sized mineral particles (approximately 40% sand, 40% silt, and 20% clay) with ample organic matter and pore space. however, some plants grow better in sandy soils, while others are well-adapted to clay soils.

2: available water capacity is the maximum amount of plant available water a soil can provide. it is an indicator of a soil's ability to retain water and make it sufficiently available for plant use. available water capacity is the water held in soil between its field capacity and permanent wilting point.

3: it is the same for all living things (plants and animals). it also includes very tiny organisms that our eyes cannot see. they are known as microorganisms, and include viruses, bacteria and fungi.