Consider statements about human anatomy: 1. The sternum is located in the chest. 2. The clavicle is the collar bone. 3. The scapula is the shoulder blade. Which are correct? MCQ with Answer and Explanation

Explanation:
The Cell Theory, one of the fundamental principles of biology, was proposed by Matthias Schleiden (a German botanist) in 1838 and Theodor Schwann (a British zoologist) in 1839. Schleiden concluded that all plants are composed of cells, and Schwann extended this to animals. Rudolf Virchow later added the third tenet in 1855: 'Omnis cellula e cellula' (all cells arise from pre-existing cells).

Explanation:
Centrioles are cylindrical microtubular structures found near the nucleus in animal cells, forming the centrosome. They organize spindle fibers during cell division (mitosis and meiosis) and are also the basal bodies of cilia and flagella. They are absent in higher plant cells. Centrioles duplicate during S phase and migrate to poles during prophase.

Explanation:
Rhodopsin (visual purple) is a photopigment in rod cells consisting of opsin and retinal (from vitamin A). It bleaches upon absorbing light, initiating signal transduction for vision in low light. Cone cells contain iodopsin for color vision. Melanin is skin pigment, hemoglobin carries oxygen.