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Explanation:
Gas exchange occurs at the alveoli in the lungs and takes place by diffusion. The alveoli are surrounded by capillaries so oxygen and carbon dioxide diffuse between the air in the alveoli and the blood in the capillaries.
Answer:
The cell organelles are the functional structures present inside the cell. Some of the organelles such as nucleus, mitochondria, chloroplast, Endoplasmic Reticulum, Golgi Complex etc are membrane-bound. Each organelle inside the cell has a different function to carry out. For example, the nucleus is the organelles which stores and protects the genetic material. Ribosomes are the organelles where a protein is formed. The Golgi- complex is the site where the proteins are modified and packaged.
Answer:
An allele (UK: /ˈæliːl/, /əˈliːl/; US: /əˈliːl/; modern formation from is one of two, or more, forms of a given gene variant.