Consider statements about plant stems: 1. Nodes are the regions where leaves arise. 2. Internodes are the regions between nodes. 3. All stems grow underground. Which are correct? MCQ with Answer and Explanation

Explanation:
Chlorophyll, mainly chlorophyll a and b, absorbs red and blue wavelengths and reflects green light, giving plants their characteristic color. It is the primary pigment of photosynthesis, located in the thylakoid membranes. Carotenoids reflect yellow-orange, phytochrome is a light-sensing pigment, anthocyanins are red/purple.

Explanation:
In humans, the intermediate lobe of the pituitary is rudimentary, and most Melanocyte-Stimulating Hormone (MSH) is produced in the anterior lobe (pars distalis). It is not synthesized as a separate hormone but is derived from the proteolytic cleavage of a large precursor polypeptide called pro-opiomelanocortin (POMC). POMC is cleaved to produce several biologically active peptides, including Adrenocorticotropic Hormone (ACTH), beta-lipotropin, beta-endorphin, and various forms of MSH (alpha, beta, gamma).

Explanation:
The Blood-Brain Barrier (BBB) is a highly selective semipermeable border that protects the brain from many substances in the blood. It is primarily formed by the tight junctions between the endothelial cells of the brain's capillaries. These endothelial cells are closely associated with the foot processes of astrocytes (a type of glial cell), which induce and maintain the tight junctions, restricting the passage of large molecules, toxins, and pathogens into the brain tissue.