Consider statements about human nutrition: 1. Scurvy is caused by Vitamin D deficiency. 2. Anemia is often caused by iron deficiency. 3. Goiter is caused by iodine deficiency. Which are correct? MCQ with Answer and Explanation

Explanation:
The pineal gland, a small endocrine gland located in the epithalamus of the brain, is often called the 'biological clock' or the 'third eye' in some lower vertebrates. Its primary function in humans is to secrete the hormone melatonin. Melatonin production is regulated by the light-dark cycle (circadian rhythm); it is produced in higher amounts during the night and suppressed by light. Melatonin helps regulate sleep-wake cycles, seasonal reproductive functions, and metabolism.

Explanation:
Phycoerythrin is a red phycobiliprotein that masks chlorophyll in red algae (Rhodophyta). Phycocyanin is blue in cyanobacteria, fucoxanthin brown in brown algae. These accessory pigments allow light absorption at depths.

Explanation:
Motor (efferent) and sensory (afferent) neurons are correctly described. Interneurons are found in the CNS, not PNS. So 3 is incorrect.