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.

What is the meaning of regeneration? Name two animals which can regenerate from of asexual their body parts.

Assertion 'Q': Due to fragmentation in Planaria, each part develops the remaining body parts and becomes a complete animal. Reasons 'R': Differentiated tissue present in each broken part of Planaria undergoes dedifferentiation and then differentiation for regeneration On the basis of assertion 'Q' and reason 'R', select the correct option.

A small cut part of organism's body can form complete new organism. This process is known as ………………….

Define transgenic animals. Explain in detail any four areas where they can be utilised.

(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?

An electromagnetic wave can be represented by E = A sin (kx- omega t + phi) , where E is electric field associated with wave, According this equation, for any value of x, E remains sinusoidal for -oolt t lt oo . Obviously this corresponds to an idealised situation because radiation from ordinary sources consists of finite size wavetrains. In general, electric field remains sinusoidal only for times of order tau_(c) ' which is called coherence time. In simpler language it means that for times of order tau_(c)' a wave will have a definite phase. The finite value of coherence time could be due to many factors, for example if radiating atom undergoes collision with another atom then wave train undergoes an abrupt phase change or due to the fact that an atom responsible for emitting radiation has a finite life time in the energy level from which it drops to lower energy level, while radiating. Concept of coherence time can be easily understood using young's double slit experiment. Let interference patten is observed around point P at time t , due to superposition of waves emanting from S_(1) and S_(2) at times t =(r_(1))/(c) and (r_(2))/(c) respectively, where r_(1) and r_(2) are the distances S_(1) P & S_(2)P . Obviously if (r_(2)-r_(1))/(c) lt lt tau_(e),{"where" " "c = 3xx10^(8)m//s} then, wavetrain arriving at point P from S_(1) & S_(2) will have a definite phase relationship and an interference pattern of good contranst will be obtained. If coherence time is of order 10^(-10) second and screen is placed at a very large distance from slits in the given figure, then:-

An electromagnetic wave can be represented by E = A sin (kx- omega t + phi) , where E is electric field associated with wave, According this equation, for any value of x, E remains sinusoidal for -oolt t lt oo . Obviously this corresponds to an idealised situation because radiation from ordinary sources consists of finite size wavetrains. In general, electric field remains sinusoidal only for times of order tau_(c) ' which is called coherence time. In simpler language it means that for times of order tau_(c)' a wave will have a definite phase. The finite value of coherence time could be due to many factors, for example if radiating atom undergoes collision with another atom then wave train undergoes an abrupt phase change or due to the fact that an atom responsible for emitting radiation has a finite life time in the energy level from which it drops to lower energy level, while radiating. Concept of coherence time can be easily understood using young's double slit experiment. Let interference patten is observed around point P at time t , due to superposition of waves emanting from S_(1) and S_(2) at times t =(r_(1))/(c) and (r_(2))/(c) respectively, where r_(1) and r_(2) are the distances S_(1) P & S_(2)P . Obviously if (r_(2)-r_(1))/(c) lt lt tau_(e),{"where" " "c = 3xx10^(8)m//s} then, wavetrain arriving at point P from S_(1) & S_(2) will have a definite phase relationship and an interference pattern of good contranst will be obtained. If coherence time is of order 10^(-10) second and screen is placed at a very large distance from slits in the given figure, then:-

A square piece of tin of side 18 cm is to be made into a box without top, by cutting a square from each corner and folding up the flaps to form the box. What should be the side of the square to be cut off so that the volume of the box is the maximum possible.

Which option shows all correct statements about fragmentation ? (I) Fragmentation is observed in spongilla, Sycon and Hydra (II) The body become fragmented in to several distinct parts. (III) Each part develops the remaining body parts and becomes a complete animals. (A) (I) (B) (I), (II) and (III) (C) (II) and (III) (D) (III)