BIOLOGY [2 Mark Question Answer]

The mist on the car windows is nothing but the condensed water vapours which we exhale out during breathing. Since the water vapours we exhale are warm but the glass windows are cold in winters, so when the water vapours come in contact with cold glass, they get converted into tiny droplets of water due to condensation.

The process of toting in oxygen and using it to break down food to release energy, carbon-dioxide and water vapour is called as respiration. It involves two stages.

• Breathing or external respiration – It involves taking in oxygen and giving out carbon-dioxide.
• Internal or cellular respiration – It involves breaking down of food in each cell using the oxygen taken in.

Autotrophs are those living beings who manufacture their own food e.g. green plants make their own food using carbon dioxide and water in the presence of sunlight and chlorophyll. Heterotrophs are those organisms which cannot make their own food and depend on plants and other animals for their food; e.g’.’-animals and non-green plants.

A living being shows movement using energy from within whereas non-living things cannot move on their own. They need external force to provide the energy to move.

Unicellular organisms like Amoeba grow with an increase in the size of the single cell whereas growth in multicellular organisms results from an increase in the number of cells.