science for 3 grade

Question: What is the importance of nutrients? Answer: The various nutrients carry out different functions such as 1) energy production 2) synthesis of materials for growth and repair of the tissues 3) synthesis of materials necessary for carrying out and maintaining life funct..

Question: The phenomenon by which the incident light falling on a surface is sent back into the same medium is known as ________. 1. polarization 2. reflection 3. refraction 4. absorption Answer: ..

Question: The percentage of nitrogen in inhaled air is _____% and exhaled air is _____%. 1. 21 and 21 2. 21 and 78 3. 78 and 21 4. 78 and 78 Answer: ..

Question: Blood is composed of ___________. 1. plasma and red blood cells 2. plasma and formed elements 3. red and white blood cells 4. red blood cells, white blood cells and platelets Answer: ..

What is the volume of 32 g of sulphur dioxide measured at S..

Question: What is 'Binomial Nomenclature'? Answer: The kind of naming in which each name has two components is called Binomial Nomenclature..

Question: Why are lysosomes called digestive bags or suicide bags? Answer: They serve as intracellular digestive system They destroy any foreign material inside the cell They also remove the worn out and poorly working cell organelles by digesting them to make way for a replacemen..

Question: Why are wrestlers and sportsmen recommended to have egg, meat and fish as a part of their diet? Answer: Sportsmen and wrestlers are recommended to have egg, meat and fish as a part of their diet because they contain high amounts of protein which is essential for growth and dev..

Question: Why do solids not diffuse into one another? Answer: Solids have very little intermolecular spaces, there by not allowing the molecules of another solid to enter. Moreover, the intermolecular force of attraction between molecules of one solid is very high and this prevents diffu..

Question: What are cathode rays? How are they formed? Answer: Cathode rays are a stream of negatively charged particles. These particles called electrons are shot from the metal cathode of a discharge tube when an electric current is passed through a gas at a very low pressure. A dischar..