(a) (i) Metamorphosis; refers to series of changes of forms or shapes from the fertilized egg (immature stage) to adult (mature stage or adulthood).
(ii) Two types of metamorphosis are: Complete metamorphosis, e.g, Butterfly, Housefly, Bees, Wasp, Beetles, Mosquito and Incomplete metamorphosis, e.g, Grasshoppers, Cockroach, Dragonfly , Locust, Aphids, Termites, Praying mantis
(b) (i) Economic importance of insects are:
(1) Act as carriers, vectors or transmitters of diseases ( e.g anopheles mosquito, tsetsefly etc
(2) Act as pests and are destructive to life plants or stored food (e.g locust; grasshoppers weevil, crickets)
(3) As food or source of protein (e.g termites, honey, larval forms of some beetles, cricket, grasshopper)
(4) Life processes involved in meiosis used in biological control (e.g lady bird - used in control of aphids on plantations, praying mantis:- control of some insects)
(5) Serve as pollinating agents of flowering plants (e.g bees, butterflies, ants, moths, wasps, beetles).
(6) Soil insects for aeration or loosening of soil (e.g termites, crickets, dung - beetles).
(7) Insects as industrial material, (bee wax for candles, silk worms).
(8) Termitarium used in building lawn tennis courts
(9) Revenue yielding - e.g termites, larva of beetles e.t.c.
(10) Destroy furniture, books, clothes, wood e.t.c, e.g cockroaches and termites.
(ii) Peculiar features of social insects are:
(1) They live together or form colonies
(2) They live in nests.
(3) Show or display division of labour.
(4) Show distinct castes.
(5) Members communicate with one another within the colonies.