Prediction tutorials

  Reproduction in Human Being :   Human beings show sexual reproduction. Male parent produces male gametes called sperms. Female parent produces female gametes called ova. Sperms have tail and are therefore, motile. They are produced in large numbers in the testes. Ovum is bigger, non-motile and only one ovary produces one ovum in one month. There is no food stored in the sperms whereas ova contain stored food. Both the gametes are microscopic unicellular and have half the number of chromosomes as compared to the body cells. Human beings become reproductively active from the onset of puberty. Puberty is the period during adolescence when the rate of general body growth begins to slow down and reproductive tissues begin to mature. Onset of puberty in human males is between 11 to 13 yrs of age, while in human females is between 10 to 12 yrs. of age. Puberty is associated with many physical, mental, emotional and psychological changes in boys and girls which occur slowly over a period of

  ORGANISMS :- An  organism  refers to a  living thing  that has an organized structure, can react to  stimuli , reproduce,  grow , adapt, and maintain  homeostasis . An organism would, therefore, be any  animal ,  plant ,  fungus ,  protist ,  bacterium , or archaeon on earth. These organisms may be classified in various ways. One of the ways is by basing upon the number of  cell s that make it up. The two major groups are the  single-celled  (e.g.  bacteria ,  archaea , and  protists ) and the  multicellular  ( animals  and  plants ). Organisms can also be classified according to their subcellular structures. Those with a well-defined  nucleus  are referred to as  eukaryotes  whereas those without are called  prokaryotes . Both of them possess a genetic material but the location differs. In eukaryotes, the genetic material is found inside the nucleus whereas, in prokaryotes, it is located in a special region called a nucleoid. Asexual Reproduction It involves only one parent. There i

  Light Light is a form of energy eyes. which produces the Sources of light are of three types-thermal sources and luminescent sources. Photometry is a branch measurement of light energy. Characteristics of Light Light waves are electromagnetic waves, whose nature is transverse. The speed of light in vacuum is 3 x 10 8  mls but it is different in different media. The speed and wavelength of light change when it travels from one medium to another but its frequency remains unchanged. Important Terms (i)   Luminous Objects  The objects which emits its own light, are called luminous objects, e.g., sun, other stars, an oil lamp etc. (ii)  Non-Luminous Objects  The objects which do not emit its own light but become visible due to the reflection of light falling on them, are called non-luminous objects, e.g., moon, table, chair. trees etc. (iii)  Ray of Light  A straight line drawn in the direction of propagation of light is called a ray of light. (iv)  Beam of Light  A bundle of the adjacent