The animal that has a notochord throughout its life is: MCQ with Answer and Explanation

Explanation:
Kala-azar, also known as visceral leishmaniasis, is caused by the protozoan parasite Leishmania donovani. It is transmitted by the bite of the infected female sandfly (Phlebotomus). The disease affects internal organs, particularly the liver, spleen, and bone marrow, causing prolonged fever, weight loss, and enlargement of the liver and spleen. Trypanosoma brucei causes sleeping sickness, and Plasmodium causes malaria.

Explanation:
All chordates, at some point during their larval or adult stages, possess three key features: a dorsal hollow nerve cord, a notochord (a flexible rod supporting the body), and pharyngeal slits. The notochord may be replaced by a vertebral column in vertebrates. Arthropods have a ventral nerve cord and open circulatory system.

Explanation:
Vitamin A is a fat-soluble vitamin stored primarily in the liver, and excess can lead to toxicity. The B-complex vitamins are water-soluble and generally not stored in the body in significant amounts. Fat-soluble vitamins (A, D, E, K) are stored in body fat and liver, making excess Vitamin D difficult to excrete, potentially causing hypervitaminosis D. Thus, statements 1 and 2 are correct.