Assertion (A): All organisms are composed of cells. Reason (R): The cell is the basic unit of life. MCQ with Answer and Explanation

Explanation:
The humerus is the single, long bone of the upper arm, connecting the shoulder to the elbow. The radius and ulna are the two parallel bones of the forearm (lower arm), connecting the elbow to the wrist. The patella, commonly known as the kneecap, is a small, flat, triangular bone located at the front of the knee joint, not in the skull. Thus, statements 1 and 2 are correct.

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:
Filippo Pacini first observed Vibrio cholerae in 1854, but Robert Koch later independently identified it and demonstrated its role. Koch is often credited, but Pacini's discovery was earlier. John Snow linked cholera to water.