The hormone responsible for the development of secondary sexual characteristics in females is: MCQ with Answer and Explanation

Explanation:
Prophase I of meiosis is divided into five sub-stages: leptotene, zygotene, pachytene, diplotene, and diakinesis. Crossing over, the exchange of genetic material between non-sister chromatids of homologous chromosomes, occurs specifically during the pachytene stage at structures called recombination nodules.

Explanation:
The Blood-Brain Barrier (BBB) is formed by tight junctions between endothelial cells in brain capillaries, making it highly selective. It allows the free diffusion of small, lipid-soluble molecules and essential gases. Therefore, oxygen, carbon dioxide, and lipid-soluble substances (like alcohol, nicotine, and some anesthetics) easily cross. Glucose, a water-soluble molecule essential for brain energy, crosses via specific carrier-mediated transport (GLUT1 transporters). Large proteins, peptides, most water-soluble drugs, and pathogens like bacteria and viruses are generally blocked from entering the brain parenchyma.

Explanation:
DNA contains the pentose sugar 2'-deoxyribose, which lacks an oxygen atom on the 2' carbon compared to ribose in RNA. This structural difference makes DNA more chemically stable and suitable for long-term genetic storage. Nucleotides consist of a nitrogenous base, a pentose sugar, and a phosphate group. Ribose is present in RNA.