The cell division that reduces the chromosome number from diploid to haploid is: MCQ with Answer and Explanation

Explanation:
The Haversian canal (central canal) is the core of the osteon (Haversian system) in compact bone. It runs parallel to the long axis of the bone and contains the blood vessels (arterioles, venules, capillaries), nerve fibers, and lymphatic vessels that supply the bone tissue. The concentric lamellae surround this canal. Osteocytes are housed in lacunae between the lamellae, and red bone marrow is found in the medullary cavity of long bones or the spaces of spongy bone.

Explanation:
The oblique entry of the ureters into the bladder creates a valve-like effect, preventing reflux. The urethral sphincter controls urination.

Explanation:
Mendel selected Pisum sativum because it had distinct contrasting traits, was easy to cultivate, and was naturally self-pollinating, allowing controlled crosses. R explains A correctly.