The structure of DNA was described as a double helix by: MCQ with Answer and Explanation

Explanation:
Lysosomes are single-membrane-bound organelles containing hydrolytic enzymes. Mitochondria, chloroplasts, and the nucleus are double-membrane-bound. Peroxisomes, vacuoles, and the endoplasmic reticulum are also single-membrane structures. The single membrane of lysosomes helps maintain an acidic pH (5.0) for enzyme activity and protects the cell from autolysis.

Explanation:
Vitamin A is chemically known as retinol. It is essential for vision, immune function, and epithelial maintenance. Vitamin B₁ is thiamine, C is ascorbic acid, D is calciferol. Deficiency of vitamin A causes night blindness and xerophthalmia.

Explanation:
Taxonomy is the branch of science concerned with the classification, identification, and naming of organisms. It involves arranging organisms into hierarchical categories based on their shared characteristics and evolutionary relationships. The study of tissues is Histology, and the study of fossils is Paleontology.