The substance used to preserve dead biological specimens is: MCQ with Answer and Explanation

Explanation:
Hemoglobin has a much higher affinity for oxygen than for carbon dioxide; it binds O2 readily in the lungs. Inside RBCs, the enzyme carbonic anhydrase rapidly catalyzes the conversion of CO2 and water into carbonic acid. Approximately 70% of CO2 is transported in the blood as bicarbonate ions in the plasma. Thus, statements 2 and 3 are correct.

Explanation:
Crossing over occurs during prophase I of meiosis, not in mitosis. Mitosis produces identical diploid cells, meiosis reduces chromosome number by half, and cytokinesis divides the cytoplasm.

Explanation:
Amphioxus (Branchiostoma) is a primitive chordate possessing a notochord, dorsal nerve cord, and pharyngeal slits throughout life, but lacking a vertebral column; hence it is an invertebrate chordate. Earthworm is an annelid, cockroach an arthropod, starfish an echinoderm—all non-chordates. Vertebrate chordates include fishes, amphibians, reptiles, birds, and mammals. Amphioxus is studied for evolutionary insights into vertebrate origins.