BS Zoology Semester Exam MCQs

Animal development often depends on hormonal signals integrated with environmental cues. In invertebrates, molting and metamorphosis are classic examples.

In open circulatory systems, hemolymph leaves vessels and bathes tissues in body cavities. Arthropods and many molluscs show this arrangement.

Fever is a systemic innate response that can slow pathogen growth and enhance immune activity. It is not antigen-specific.

The lateral line detects water displacement, allowing fishes to respond quickly to pressure waves from predators, prey, or obstacles.

Touch receptors respond to mechanical deformation of skin. They are mechanoreceptors specialized for pressure or vibration rather than light.

Multicellular animals require communication to coordinate movement, feeding, defense, reproduction, and internal stability across specialized tissues.

Juvenile hormone helps maintain larval features. Declining juvenile hormone allows metamorphic progression toward pupal or adult stages.

In aquatic environments, vibrations and water movements can reveal prey even in darkness. A lateral line is specialized for this mechanosensory task.

Sensory organs detect stimuli, but the nervous system transmits and processes those signals to produce perception or response.

Insulin promotes glucose uptake and storage, reducing blood glucose after meals. It is secreted by pancreatic beta cells and acts through target-cell receptors.

Some crustaceans use neuroendocrine hormones to move pigments within chromatophores, changing body coloration for camouflage or signaling.

Sensory cells generally require a minimum stimulus intensity before producing a receptor potential strong enough to signal the nervous system.