The concentric rings of calcified intercellular substance arranged around haversian
canals are called:
a) lamellae
b) lacunae
c) trabeculae
d) canaliculi
e) collagen fibers

The concentric rings of calcified intercellular substance arranged around Haversian  canals are called Lamellae

Explanation:

The microscopic tubes situating at the outer region of cortical bone which gives way to the nerves and blood vessels to travel through it is referred to as Haversian canals.  The channels of the canals are composed of concentric substance called Lamellae.

It surrounds the nerve cells and vessels of bones and makes a communication with cells of the bone through canaliculi. Lamellaes compose concentric rings made up of calcified intercellular substance around the tissue of bones.

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"menstrual cycle is a complex cycle that consists of several processes. order of occurrence of steps in menstrual cycle are as follows:

1. high progesterone levels maintain the endometrium lining of the uterus.

2. endometrium lining breaks down and low levels of estrogen stimulate the pituitary to release fsh and lh.

3. fsh and lh stimulates the follicles to develop and the oocyte to produce estrogen.

4. rising estrogen levels suppress fsh production and development of other follicles.

5. a spike in lh causes follicle to rupture.

6. a breakdown of corpus luteum causes progesterone level to drop."