(a) Dentition in animals refers to the arrangement, number, and type of teeth in their mouth. It is an important feature that helps animals to eat and digest food properly.
(b) The general structure of a tooth in animals consists of three main parts:
- Crown: The visible part of the tooth that is covered by enamel, which is the hardest substance in the body. The crown is used to bite and chew food.
- Neck: The part of the tooth that connects the crown to the root.
- Root: The part of the tooth that is embedded in the jawbone and holds the tooth in place. The root is covered by a layer of cementum, which helps to anchor the tooth to the jawbone.
Inside the tooth, there is a pulp cavity that contains blood vessels and nerves. The pulp cavity is protected by dentin, which is a hard, bonelike substance that surrounds the pulp.
(c) Three food substances that plants manufacture from glucose are:
- Starch: Plants store glucose as starch, which is a complex carbohydrate that can be broken down into glucose when needed for energy.
- Cellulose: Plants also use glucose to make cellulose, which is a structural carbohydrate that makes up the cell walls of plant cells.
- Sucrose: Plants produce sucrose, a disaccharide made up of glucose and fructose, which is used for energy storage and transport.
(d) Diagram of an experimental set-up to show that oxygen is produced during photosynthesis:
To set up this experiment, you will need a beaker filled with water, a plant (such as Elodea), a light source, and a test tube. Follow these steps:
- Fill a beaker with water and place a stem of Elodea in the water.
- Invert a test tube over the end of the stem, so that the test tube is completely filled with water.
- Place the beaker and Elodea under a light source for several hours.
- Observe the test tube and you will see that oxygen bubbles have been produced and collected at the top of the test tube.
This shows that oxygen is produced during photosynthesis as a byproduct, and the experiment demonstrates the process of photosynthesis.
The diagram should show the beaker with water, the stem of Elodea, the test tube filled with water and inverted over the stem, and the light source shining on the set-up. It should also clearly show the oxygen bubbles collected at the top of the test tube.