Consider statements about human immunity: 1. Colostrum provides passive immunity to infants. 2. Allergies are exaggerated immune responses. 3. Autoimmune diseases occur when the immune system attacks self-cells. Which are correct? MCQ with Answer and Explanation

Explanation:
TSH, released from the anterior pituitary, binds to receptors on thyroid follicular cells, stimulating the synthesis and release of thyroxine (T₄) and triiodothyronine (T₃). TSH release is regulated by thyrotropin-releasing hormone (TRH) from the hypothalamus and feedback inhibition by thyroid hormones. ACTH stimulates adrenal cortex, GH growth, prolactin milk production.

Explanation:
Aldosterone is a mineralocorticoid hormone secreted by the zona glomerulosa, the outermost layer of the adrenal cortex. Its primary function is to regulate electrolyte balance by promoting the active reabsorption of sodium (Na+) and the excretion of potassium (K+) and hydrogen ions (H+) in the distal tubules and collecting ducts of the kidneys. The zona fasciculata secretes glucocorticoids (cortisol).

Explanation:
RNA contains uracil instead of thymine found in DNA. In DNA, adenine pairs with thymine; in RNA, adenine pairs with uracil. Adenine, guanine, and cytosine are common to both. Uracil is a pyrimidine base, structurally similar to thymine but lacking a methyl group. This distinction is used in genetic material identification and understanding transcription.