BS Zoology Semester Exam MCQs

Chemical synapses depend on neurotransmitter release from the presynaptic neuron. Without release, the next neuron or effector receives little or no signal.

Earthworms move when circular muscles lengthen segments and longitudinal muscles shorten them. The hydrostatic skeleton gives resistance for these shape changes.

Amoeboid movement uses cytoplasmic streaming and pseudopodia rather than muscle fibers. It is a cellular locomotion mechanism.

Muscular systems are not required in unicellular or very small organisms. Protozoans and many cells move by cilia, flagella, pseudopodia, or cytoplasmic streaming.

In a withdrawal reflex, receptors detect heat or pain, neurons carry signals, and skeletal muscles act as effectors to move the limb away.

Keratin is a tough structural protein in hair, nails, claws, and epidermis. It strengthens integumentary derivatives and improves protection.

Amoeba extends pseudopodia through changes in cytoplasm. This movement also helps engulf food by phagocytosis.

Cilia generate movement at the cellular level, while muscles act as tissues and organs. Both contribute to locomotion or movement of materials.

Mechanoreceptors detect mechanical forces such as pressure, touch, vibration, stretch, or sound. They convert mechanical stimuli into nerve impulses.

Paramecium uses coordinated ciliary beating for swimming and feeding currents. It lacks muscles and a skeleton, so movement is cellular rather than organ-system based.

Amphibian skin is moist and permeable, allowing water loss in dry conditions. This makes humid habitats important for many amphibians.

Chitin, scales, and feathers are different body coverings, but all contribute to protection. Some also support movement, insulation, or display depending on the animal.