The marine algae that form the basis of many aquatic food chains and produce much of Earth's oxygen are: 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 hepatic lobule is the basic structural and functional unit of the liver, consisting of plates of hepatocytes radiating from a central vein. Bile canaliculi, sinusoids, and portal triads are key features. Nephrons are kidney units, alveoli lung units, islets pancreatic endocrine units.

Explanation:
The epididymis is a coiled tube on the testis where sperm mature and are stored. Seminal vesicles and prostate add fluid, vas deferens transports sperm.