Name two inorganic substance which are used by autotrophs to make food.

Name two inorganic substances required by autotrophs to carry on photosynthesis.

Name two substances which can be used as olfactory indicators ?

Name two useful substances which are produced by the treatment of sewage . state their uses.

Name the substance which is used in lubrication :

Name the brown algae which are used as food

Name two inorganic impurities present in sewage.

Name two inorganic impuritise present in sewage.

Name two domestic animals which are used as food source.

Name two inorganic compounds which can be used as semipermeable membranes. Describe briefly the preparation of cupric ferrocyanide membrane.

Name the teeth which are used for chewing food.