Terrestrial animals are generally either ureotelic or uricotelic, not ammonotelic, why?

* Cells are generally isodiametric * Cells may be spherical, oval, rounded, polygonal or elongated inn shape. * Their walls are thin and made up of cellulose. * The cells may either be closely packed or have intercellular spaces. Above characters of cells related to which type of simple permanent tissue?

The taxonomic studies of various species of plants and animals are useful in agriculture, forestry, industry and in general for knowing our bio-resources and their deversity. (True/False)

Medicines are either man made (i.e., synthetic) or obtained from living organisms like plants, bacteria, animals, etc. and hence, the latter are called natural products. Sometimes, natural products are chemically altered by man to reduce toxicity or side effects. Write against each of the following whether they were initially obtained as a natural product or as a synthetic chemical. (a) Penicillin (b) Sulphonamide (c) Vitamin-C (d) Growth hormone

Why are offspring of oviparous animals at a greater risk as compared to offspring of viviparous animals ?

If any animal is cut into many pieces, can a new complete animal body be generated from each piece? If yes, then explain such event.

Comets move around the sun in highly elliptical orbits . The gravitational force on the comet due to the sun is not normal to the comet's velocity in general. yet the work done by the gravitational force over energy complete orbit of the comet is zero . Why ?

(i) A poor emitter has a large reflectivity . Explain why. (ii) A copper tumbler feels much colder than a wooden block on a cold day. Explain why. (iii) The earth would become so cold that life is not possible on it in the absence of the atmosphere. Explain why? (iv) Why clear nights are cooler than cloudy nights? Why does a piece of red glass when heated and taken out glow with green light? (vi) Why does the earth not become as hot as the sun although it has been receiving heat from the sun for ages? (vii) Animals curl into a ball when they are very cool. Why? (viii) Heat is generated continuously in an electric heater but its temperature becomes constant after some time. Explain why? (ix) A piece of paper wrapped tightly on a wooden rod is observed to get charred quickly when held over a flame as compared to a similar piece of paper when wrapped on a brass rod. Explain why? (x) Liquid in a metallic pot boils quickly whose base is made black and rough than in a pot whose base is highly polished . Why?