Answer:
Human activities cause the emission of halogen source gases that contain chlorine and bromine atoms. These emissions into the atmosphere ultimately lead to stratospheric ozone depletion.
Explanation:
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Answer:
The correct answer would be D.Alveolar sacs are surrounded by thin capillaries where gases can be exchanged.
Alveoli are tiny sacs which form the site of gas exchange in the lungs.
The features of alveoli which help in gas exchange are:
- They increase the surface area in the lungs thus, more space is available for gas exchange.
- They have very thin walls, as thin as the thickness of a single cell only.
- They are surrounded by a bunch of thin capillaries which exchange gases with alveoli.
Answer:
A - DNA
B - mRNA
C - nuclear pore
D - tRNA
E - ribosome
F - rRNA
Explanation:
<em>The entire structure illustrates the process of transcription and translation in a typical eukaryotic cell.</em>
The DNA (A) in the nucleus of the cell is first transcribed to mRNA (B). The mRNA produced is transported to the cytoplasm through the openings within the nuclear membrane - the nuclear pores (C). On getting to the cytoplasm, the mRNA binds to the ribosome (E) (carrying rRNA, F). The tRNA (D) carrying the specific anticodon for a particular codon on the mRNA then binds to the structure and the corresponding amino acid is released. A polypeptide bond is formed between subsequent amino acids and the ribosome moves along the mRNA chain until the translation process is complete.