<span>Plants without vascular system are non-vascular plants. Non-vascular plants have no xylem and no phloem.
Non-vascular plants include algae, bryophytes, moss grass, liverworts and hornworts.
The answer to this item is moss. Moss is a non-vascular plant which has no seeds and no flowers. It uses spores in reproduction.</span>
Mechanical stress applied to bone increases osteoblast activity in bone tissue, and the removal of mechanical stress decreases osteoblast activity.
Explanation:
Osteoblasts are cells , that are produced in the bone marrow and are responsible for formation of bones and bone matrix.
Whenever a mechanical stress is applied on the bones , a series of reactions are triggered. As a result the activities of osteoblast increases to synthesize more and more bone matrix to provide strength.
Again on the other hand a decrease in mechanical causes a decrease in the activities of the osteoblasts.
