fourth grade science book

Botanical survey of India publishes this book. This book provides information about plant species which are rare, endangered or endemic, but all of which are grown in botanical garden..

> Atomatic number of the elements 1st Period n = 1 Short period 2 Atomic number 1 and 2 2nd Period n = 2 Short period 8 Atomic number 3 to 10 3rd Period n = 3 Long period 8 Atomic number 11 to 18 4th Period n = 4 Long period 18 Atomic number 19 to 36 5th Peri..

When a force acts on an object and the object moves in the direction of force, we say that the force has done work on the object. If you push a book lying on a table you exert force on the book and the book moves in the direction of the force. We say that the force h..

Matter and its Forms - Take a look at your surroundings. You may find a pencil, a book, an apple, a table or a chair. Can you feel the air blowing? These are different forms of matte..

Question: Respiration in arthropods occurs through 1. gills 2. book lungs 3. trachea 4. all the above Answer: 4..

Question: A long-sighted person cannot see objects nearer to his eye than 50 cm. To enable him to read a book 25 cm away, he should use spectacle lenses whose power in dioptres is ____. 1. -6 2. -4 3. -2 4. + 4 Answer: 4..

Hold your bag with a strap made of a thin but strong string. Now lift the same bag with another strap made of a wide cloth band. You will find that carrying a school bag with a wide cloth band is more comfortable than carrying the same with a thin strip. This is because in the second case the weigh..

Features of Arthropoda..

Hypermetropia - You must have seen middle aged people holding a book away from their eyes to read properly. This is because they are not able to see the nearby objects clearly. We say that those people are suffering from hypermetropia (long sightedness). Hypermetropia or hyperopia is an e..

Myopia - You must have seen some people holding books very close to their eyes. This is because they suffering from myopia (short sightedness). A myopic person cannot see distant objects clearly because the far point of his eye is less than infinity. Myopia is an eye defect due to which t..