Insects which carries germs of diseases are called___________.
Vectors:
Final answer: Insects that carries germs of diseases are called vectors.
A is an insect which breeds in ponds of stagnant water. The egg of this insect produces a worm like form B which is entirely different in appearance from the adult insect. The form B undergoes a change C and gets converted into insect A. The female of insect A is a carrier of protozoan D which spreads a disease in humans.
(a) What are A, B, C and D ?
(b) Name another insect which also undergoes change C.
The cells in our blood which destroy disease-causing germs, are : (a) platelets (b) skin cells (c) RBCs (d) WBCs
What will happen if −
(a) Forests, scrub and other vegetation is reduced.
(b) Sewage carrying dangerous chemicals enters rivers.
(c) Birds eat insects which have been killed by insecticides.
(d) Poisonous substances are overused to prevent insects from destroying a crop.
(e) A dam is built in a famine-prone region.
Communicable diseases can spread to a healthy person through disease-causing germs called ___.