Echinoderms are deuterostomes.

In deuterostomes:

• The blastopore becomes the anus.

• The coelom forms by the outpocketing of the archenteron, called enterocoely.

Spiral cleavage and determinate development are characteristics of protostomes, not deuterostomes.

Last updated question 25 feb 2026

The hypothalamus monitors nutrient levels and energy balance.

It controls hunger and satiety centers, regulating food intake.

Cerebellum is for coordination, and pineal gland regulates circadian rhythms, not feeding.

Last updated question 25 feb 2026

Nematodes have a pseudocoelom filled with fluid.

This fluid under pressure acts as a hydrostatic skeleton, maintaining body shape and supporting movement.

They do not have a rigid exoskeleton, so hydrostatic pressure is key.

Last updated question 25 feb 2026

Social hierarchy mainly reduces conflicts and competition within the group.

It helps maintain order, access to resources, and mating opportunities, rather than reducing lifespan, increasing predation, or eliminating communication.

Birds have air sacs connected to lungs.

Air flows in one direction through the lungs during both inhalation and exhalation.

This ensures efficient oxygen exchange to support high metabolism.

Air sacs do not primarily store oxygen.