The structure that prevents food from entering the trachea is the: MCQ with Answer and Explanation

Explanation:
Double fertilization involves one male gamete fusing with the egg cell to form a diploid zygote, and the second male gamete fusing with the two polar nuclei (central cell) to form a triploid primary endosperm nucleus. The endosperm provides nutrition to the developing embryo. This unique feature ensures efficient nutrient supply and is typical of angiosperms.

Explanation:
The genetic code is read in triplets of nucleotides called codons, each specifying an amino acid. AUG is the universal start codon, which also codes for methionine. In eukaryotic genes, introns are non-coding intervening sequences that are spliced out, while exons are the coding sequences that remain in the mature mRNA. Thus, statements 1 and 2 are correct.

Explanation:
Insulin is a peptide hormone produced by the beta cells of the Islets of Langerhans in the pancreas. It is initially synthesized as a single, inactive polypeptide precursor called proinsulin. During processing, a connecting peptide (C-peptide) is removed, leaving two polypeptide chains: the A chain (21 amino acids) and the B chain (30 amino acids). These two chains are held together by two interchain disulfide bridges (covalent bonds between sulfur atoms of cysteine residues), and there is also one intrachain disulfide bridge within the A chain.