Tag: oviparous and viviparous

Insects shed their exoskeleton in order to grow which is known as moulting. Moulting allows the body of insects to expand under protected conditions. An instar is a developmental stage of insects, between each moult until sexual maturity is reached.

• Molting hormone or Ecdysone is produced by the prothoracic glands which regulates metamorphosis.
  
• It's principle function is to stimulate a series of physiological events (collectively known as apolysis) that lead to synthesis of a new exoskeleton.
• During this process, the new exoskeleton forms as a soft, wrinkled layer underneath the hard parts (exocuticle plus epicuticle) of the old exoskeleton.
  

So, the correct option is 'Ecdysone'.

Winged adults lay eggs on the food plant on which their larvae, known as caterpillars, will feed. The caterpillars grow, sometimes very rapidly, and when fully developed pupate in a chrysalis. When metamorphosis is complete, the pupal skin splits, the adult insect climbs out and, after its wings have expanded and dried, it flies off. Some butterflies, especially in the tropics, have several generations in a year, while others have a single generation, and a few in cold locations may take several years to pass through their whole life cycle.

In complete metamorphosis, organism passes through four distinct stages in their life cycle. Moths pass through caterpillar and pupa stage while reaching from egg to adult stage, hence they undergo complete metamorphosis.

• The process of growth and metamorphosis in insects is controlled by secretions of prothoracic glands and corpora allata which are ecdysone and juvenile hormone respectively.
  
• Ecdysone stimu­lates growth and shedding of the old cuticle of the larva and the new cuticle is formed beneath the old cuticle.
  
• The juvenile hormone keeps the larval cells active and also controls the qualitative changes in the body during metamorphosis.
  

So, the correct option is 'Juvenile hormone' and 'Ecdysone'.

Metamorphosis is a biological process by which there is a profound change in form from one stage to the next in the life history of an organism, as from the caterpillar to pupa and from the pupa to adult. Some insects, fishes, amphibians, molluscs, crustaceans, cnidarians, echinoderms and tunicates undergo metamorphosis. Humans do not undergo metamorphosis.
So, the correct answer is 'Both B and C'

Neurology is the study of structure and function of neurons.