The specific part of the respiratory system where gas exchange occurs is the: MCQ with Answer and Explanation

Explanation:
Proteins are polymers of amino acids. The amino acids are linked together by peptide bonds, which are covalent bonds formed between the carboxyl group (-COOH) of one amino acid and the amino group (-NH2) of the next, with the release of a water molecule (dehydration synthesis). Glycosidic bonds link sugars, and phosphodiester bonds link nucleotides.

Explanation:
The medulla oblongata is the lowest part of the brainstem, connecting the pons to the spinal cord. It contains vital autonomic centers that control essential, involuntary life-sustaining functions. These include the cardiovascular center (regulating heart rate and blood vessel diameter), the respiratory center (regulating the rate and depth of breathing), and reflex centers for vomiting, coughing, sneezing, and swallowing. Damage to the medulla is often fatal due to the cessation of these vital functions.

Explanation:
P700 is the reaction center chlorophyll a of photosystem I, absorbing light at 700 nm. It donates electrons to ferredoxin. P680 is the reaction center of PSII. Chlorophyll b and carotenoids are accessory pigments. The two photosystems work in series to transfer electrons from water to NADP⁺.