The correct answer is:(d) (iii) and (iv) Cardiac muscles and smooth muscles act involuntarily. Cardiac muscles are found in the heart and contract automatically, while smooth muscles are found in internal organs like the stomach and intestines, controlling movement without ...

The correct answer is:(c) Mitosis Mitosis is the type of cell division responsible for growth, development and repair in multicellular organisms. It produces genetically identical diploid cells, ensuring the body’s tissues grow and regenerate without altering genetic information. Class 9th ...

The correct answer is:(a) Virchow Rudolf Virchow (1855) proposed the famous statement “Omnis cellula e cellula,” meaning “cells arise from pre-existing cells.” This idea contributed to the Cell Theory, emphasizing that cell division is the basis of life. Class 9th ...

The correct answer is:(d) Both (b) and (c). The contractile vacuole in unicellular organisms like Amoeba and Paramecium helps in osmoregulation by expelling excess water and also aids in excretion by removing metabolic wastes, maintaining the cell’s internal environment. Class ...

The correct answer is (a) 10⁻⁶ m. 1 micrometer (µm) = 10⁻⁶ meters, which means it is one-millionth of a meter. It is commonly used to measure cell sizes, bacteria and microscopic structures in biology and microbiology. Class 9th Science ...