Trypanasoma is a protozoan animal. It lives as a parasite in the blood and later invades the cerebrospinal fluid to cause the sleeping sickness. This parasite is transmitted by the Tsetse fly.

A 40% solution of Formaldehyde known as Formalin is used in the preservation of biological specimens because of its hardening action on proteins. 

Terylene and nylon are synthetic fibres produced by a process of polymerisation. Terylene is a polyester and nylon, a poyamide.

Silk is purely a natural product obtained from silk worms.

Rayon is a man-made material which consists of purified cellulose in the form of long fibres. Cellulose occurs in the cell wall of plants. Rayon fibre is chemically identical to cotton but has a shine like silk. Since it is  basically derived from a natural source (cellulose) it is called a regenerated fibre.

Vapour of carbon tetra chloride ccl4 is non-inflammable and is heavier than air. Hence it is used as a fire extinguisher under the trade name of pyrene.

A closed room is aplace where charcoal is burnt in limited supply of air. There is every chance for the formation of the deadly poisonous carbon monoxide, which when inhaled, reacts with the iron in haemoglobin of blood and prevents the supply of oxygen. It is said to be treacherous as there can be no previous warning of its presence because it is an odourless and colourless gas.

Parabola, because when the coin is dropped at a particular point, it has the same velocity as the running train. So, by Newton's first law, it continues its motion horizontally with that velocity. But then, it is also pulled down by earth's gravity continuously. In this situation its horizontal motion gives way to the parabolic motion until it reaches the ground.

The size of the pupil of the automatically adjusts itself according to the intensity of light passing through it; if the intensity is more, the size is less, if less, it is more. So in our case the pupil should dilate i.e , increase in size to be able to see in the dark. This switchover takes some time. But here the entry into the dark room is immediate. So the eye has no time to adjust itself and hence is not able to see at all for a while.