Osteons are the basic organizational units of spongy bone compact bone bone marrow procalluses

Option B , compact bone

Explanation:

Osteon is the major organizational unit of compact bone. Compact bone is also known as cortical bone which consists of concentric layers of bone called as lamellae. Haverisan canal is lined by these concentric bones which supply blood to the osteocytes. Osteons are parallel thread like structure which are some 0.01  to 0.02  millimeter in diameter and run along the longer bone axis.

Hence, option B is correct.

hey, i believe your answer would be d. sugar ribose and the base uracil. i believe this is the answer, because rna consists of sugar ribose, adenine, guanine, cytosine, and uracil.

your first option is incorrect, because that's dna. where it consists of sugar deoxyribose, adenine, guanine, cytosine and thymine.

your second option is also incorrect, this is because sugar deoxyribose is in dna, and uracil is in rna. these two do not make sense together.

your third option being incorrect, because sugar ribose is in rna, but not the base of thymine. rna consists of uracil, not thymine.

lastly your fourth option being correct! this answer is correct, because both sugar ribose, and the base uracil are in rna! ~

answer is d. sugar ribose and the base uracil.