How can you test for the gas produced

Explanation:

Tests for gases

Hydrogen, oxygen, carbon dioxide, ammonia and chlorine can be identified using different tests.

Hydrogen. A lighted wooden splint makes a popping sound in a test tube of hydrogen.

Oxygen. A glowing wooden splint relights in a test tube of oxygen.

answer:

the water molecules are transferred from the roots to the stem or top parts of the tall tree because of important properties of water which are adhesion, cohesion and capillary action. cohesion is the property of water molecules keeps water molecules in a combined state by sharing of bonds between them at the atomic level. adhesion allows the interaction of water molecules with other substances or substrate. adhesion will cause the attachment of water molecules to the wall of the vessel (xylem) of the plant. capillary action occurs when the adhesive force to the vessel wall is stronger than the cohesive force between water molecules. capillary action mimics the transfer of water from a tube or pipe. in this way water utilizes its property to transfer water from down to top level of the plant.  

b is the correct answer