Which of the following is an example of a biological macromolecule?

The correct answer is D. Cardiac muscles contain intercalated discs, whereas skeletal muscles do not. Intercalated discs are unique features of cardiac muscle cells, providing a structural and functional connection between adjacent cells. Skeletal muscles lack intercalated discs.

The correct answer is C. The complementary strand of DNA will have bases that pair with the original strand according to the base-pairing rules. In DNA, adenine (A) pairs with thymine (T), and guanine (G) pairs with cytosine (C). Therefore, the complementary strand reads 3’ TCGATCGCA5’.

The correct answer is C. Chlorine molecule (Cl2) has only one covalent bond between the two chlorine atoms, which share one pair of electrons. The other molecules have more covalent bonds: water has two, methane has four, and ammonia has three.

The correct answer is B. Uracil is a nitrogenous base found in RNA, replacing thymine which is found in DNA. Adenine, guanine, and cytosine are common to both RNA and DNA.

The correct answer is A. Chromatin is a complex of DNA and proteins, including histones, found in the nucleus of eukaryotic cells. It carries the hereditary information in the form of genes. ATP, plasmids, and histones are involved in cellular processes but do not carry hereditary information.

The correct answer is C. The renal vein is responsible for draining oxygen-depleted blood from the kidneys. After the kidneys filter waste and excess substances from the blood, the deoxygenated blood is carried away from the kidneys by the renal vein

The correct answer is B. Atoms become cations by losing electrons. Potassium has one electron in its outermost shell, and it is more likely to lose that electron to achieve a stable, cationic state. Fluorine, helium, and oxygen are more likely to gain electrons and form anions.

The correct answer is A. The endocardium is the innermost layer of tissue that lines the interior surfaces of the heart, providing a smooth surface for blood flow. The myocardium is the middle muscular layer, the pericardium is the outer protective sac, and the epicardium is the outermost layer covering the heart.

The correct answer is A. Melanocytes are responsible for producing the pigment melanin and transferring pigment granules to adjacent epidermal cells, particularly keratinocytes. This process contributes to the coloration of the skin.

The correct answer is C. Psoriasis is a chronic autoimmune skin condition characterized by the rapid buildup of skin cells, and it is considered a noninfectious disease. Chikungunya, dengue, and brucellosis are infectious diseases caused by specific pathogens.