PROTO-ONCOGENES are corresponding normal cellular genes to an oncogene that is responsible for normal cell growth and division.
An oncogene refers to a gene that is capable of causing cancer due to damage to the DNA molecule either by virus or other DNA damaging agents. A proto oncogene is the normal version of the gene while an oncogene is the abnormal version of the concerned gene.
Answer:
cardiovascular and respiratory systems
Explanation:
the cardiovascular system includes your heart and blood vessels, which function to remove deoxygenated blood from and return oxygenated blood throughout your body
The correct answer is option (d) They allow the exchange of gases between cells in the leaf and the external environment.
Stomata are the tiny openings present in the epidermis (outer layer of cells) of the leaf. They have a pore which is guarded by the guard cells which controls the opening and closing of the stomata. Air enters and exits through the stomata.
The main funtion of stomata is to facilitate the gaseous exchange. The gas exchange that occurs when the stomata are open helps in the process of photosynthesis. During photosynthesis, carbon dioxide is taken in from the atmosphere and oxygen is released as a by-product of photosynthesis. The glucose produced is converted into the starch and stored in the leaves.
Also, water vapour diffuses through the stomata into the atmosphere by a process called the transpiration.
Thus, stomata are the structures that are mainly involved in the gaseous exchange between the cells of the leaf and the atmosphere.
Which statements describe why organisms are classified? Check all that apply.
1. Classification shows how closely related organisms are to each other.
2. Classification makes organisms easier to study.
3. Classification allows for better identification of new organisms.
The grouping system makes it easier for scientists to study certain groups of organisms.
