Cell division is the process essential for growth and repair in multi-cellular organisms.
Injury to the tissue can activate surrounding cells to undergo cell division with the help of mitogens. Mitogens are the chemical substances which help in escalating mitotic divisions in the cells.
They act by activating the signal-transduction pathway which involve mitogen-activated protein kinase (MAPK).
Other possible manner could be the loss of density which could lead to the inactivation of contact inhibition. As there is a loss of cells during the injury, it makes an empty space which could also trigger or activate surrounding cell to start cell division.
In addition, at injury site the flow of blood also increases to transport various nutrients, clotting factors, growth factors etc. These increased nutrition and growth factors also speed up the process of mitosis.
Answer:
Lower Respiratory Tract
Explanation:
The lower respiratory tract or lower airway is derived from the developing foregut and consists of the trachea, bronchi (primary, secondary and tertiary), bronchioles (including terminal and respiratory), and lungs (including alveoli). It also sometimes includes the larynx, which we have done here. This is where gas exchange actually takes place.
The Atria Are the Heart's Entryways for Blood
The left atrium and right atrium are the two upper chambers of the heart. The left atrium receives oxygenated blood from the lungs. The right atrium receives deoxygenated blood returning from other parts of the body.
The heart
Answer:
heart blood vessels and blood
Answer:
B) ecological succession
Explanation:
The analogy given in this question describes ECOLOGICAL SUCCESSION, which is the series of changes that an ecosystem undergoes over a period of time. Ecological succession is of two types viz: Primary succession and Secondary succession.
Primary succession involves the series of changes that occurs on a new habitat that has never been previously colonized. This is the case of the colonization of bare rocks with no plant life by LICHENS. The action of the lichen, which involves secretion of acids that disintegrates the rocks into soil, paves way for the colonization of that area by new species.
Lichens, via the role they play in primary succession by helping alter a barren area into a fertile one that accommodates other organisms, makes them be regarded as PIONEERS of primary succession.
