Assertion (A): Plants take in carbon dioxide and release oxygen during the day. Reason (R): Photosynthesis produces oxygen as a byproduct. MCQ with Answer and Explanation

Explanation:
Amoeba, a protozoan, moves and captures food using temporary, foot-like extensions of its cytoplasm called pseudopodia (false feet). This type of movement is called amoeboid movement and is driven by the assembly and disassembly of microfilaments (actin) in the cytoskeleton. Cilia and flagella are hair-like structures used by other protozoans like Paramecium and Euglena.

Explanation:
The fluid mosaic model, proposed by Singer and Nicolson (1972), describes the plasma membrane as a phospholipid bilayer with proteins floating like icebergs in a sea of lipids. It accounts for membrane fluidity and selective permeability. The cell wall is rigid, nucleus has a double membrane, ribosome is a ribonucleoprotein complex.

Explanation:
The question describes sieve elements, which are the conducting cells of the phloem, not xylem. Sieve tube elements are living but lack a nucleus at maturity and have perforated end walls called sieve plates. Xylem vessels and tracheids are dead, hollow, and lack perforated end walls (vessels have perforation plates, but they are not called sieve plates). Xylem parenchyma is living.