The structure that prevents food from entering the nasal cavity during swallowing is the: MCQ with Answer and Explanation

Explanation:
The root is divided into zones. The root hair zone contains epidermal extensions (root hairs) that vastly increase surface area, making it the primary region for water and mineral absorption. The zone of cell division (meristematic zone) is at the very tip, where active mitosis occurs; the zone of elongation is where cells expand in length, pushing the root tip forward. The root cap is a thimble-like structure protecting the delicate apical meristem as it pushes through soil. Thus, statements 1 and 3 are correct.

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:
Fossils are the preserved remains or traces of ancient organisms, providing crucial evidence for evolution. Analogous organs (like wings of birds and insects) perform similar functions but have different structural plans and evolutionary origins, indicating convergent evolution. Jean-Baptiste Lamarck proposed the theory of inheritance of acquired characters, while Charles Darwin proposed natural selection. Thus, statements 1 and 2 are correct.