Archaeopteryx is considered a connecting link between: MCQ with Answer and Explanation

Explanation:
Streptomycin is an antibiotic produced by the bacterium Streptomyces griseus. Penicillin and cephalosporins are from fungi (Penicillium and Cephalosporium). Griseofulvin is a fungal antibiotic. Streptomycin is a broad-spectrum aminoglycoside, effective against gram-negative bacteria and Mycobacterium tuberculosis. It inhibits bacterial protein synthesis by binding to the 30S ribosomal subunit.

Explanation:
Norman Myers introduced the concept of biodiversity hotspots in 1988—regions with high endemic species and significant habitat loss (≥70% original vegetation lost). Examples: Western Ghats, Indo-Burma. Conservation efforts prioritize these areas. Darwin contributed evolution, Humboldt to biogeography, E.O. Wilson is known for sociobiology and biodiversity studies. Hotspots cover only 2.4% of Earth's land but hold >50% of plant species.

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.