B. their fuction is a result of their shape and folding
Answer:
The osteoblasts, which should have been building the new bone
Explanation:
Bones are the one of the types of connective tissues and have hard extracellular matrix. Osteoblasts are the cells that serve in formation of extracellular matrix of bones as these cells secrete collagen fibers and inorganic salts present in the matrix of bone. Hence, if a bone is not able to heal after fracture, osteoblast cells should be checked for their activity.
Answer:
Option A, oxygen in the atmosphere
Explanation:
The highest level of oxygen reached during this phase of the geological cycle of earth. The oxygen level in Carboniferous period accounted for 35% as compared to 21% of oxygen in the atmosphere in present time.
Due to high oxygen content, the giant and wide varieties of terrestrial animal and plant species evolved. For example – size of insects and carwlies increased, plant became extremely giant, increase in number of tree ferns etc.
