std 7th
subject science
Answers
Answer:
1. Parasite : Parasite is an organism that lives on or in another organism (called host) using it as source of food and a place a temporary or permanent residence.
Saprophyte : Saprophyte is an organism that feeds on a decomposing matter from dead organism. Saprophyte feed with decaying organism matter from dead organism.
2. Amoeba : Amoeba engulfs its food by surrounding the food particle with its pseudopodia. The undigested food which is largely carbon dioxide gas is expelled outside by the vacuole.
Human beings : While human beings, the food (which is a complex substance) is taken inside the mouth and undergoes a complex process of digested and absorption.
3. Physical change : Physical changes only change the appearance of a substance, not its chemical composition.
Chemical change : Chemical changes cause a substance to change into an entirely substance with a new chemical formula.
4. Acid : Acid is a kind of chemical compound that when dissolved in water gives a solution with H+ ion activity more than purified water.
Base : A base is an aqueous substance that donates electrons, accept protons or release hydrogen (OH-) ions.
5. Conductors : Conductors are materials that permit electrons to flow freely from particle to particle. Conductors allow for change transfer through the free movement of electrons.
Insulators : Insulators are material that impede the free flow of electrons from atom and molecule to molecule.