Read the following passage and mark the letter A, B, C, or D to indicate the correct answer to each of the questions
THE BALANCE OF NATURE
All the different plants and animals in a natural community are in a state of balance. This balance is achieved by the plants and animals interacting with each other and with their non-living surroundings. An example of a natural community is a woodland, and a woodland is usually dominated by a particular species of plant, such as the oak tree in an oak wood. The oak tree in this example is therefore called the dominant species but there are also many other types of plants, from brambles, bushes, and small trees to mosses, lichens and algae growing on tree trunks and rocks.
The plants of a community are the producers: they use carbon dioxide, oxygen, nitrogen to build up their tissues using energy in the form of sunlight. The plant tissues form food for the plant-eating animals (herbivores) which are in turn eaten by flesh-eating animals (carnivores). Thus, plants produce the basic food supply for all the animals of a community. The animals themselves are the consumers, and are either herbivores or carnivores.
Examples of herbivores in a woodland community are rabbits, deer, mice and snails, and insects such as aphids and caterpillars. The herbivores are sometimes eaten by the carnivores. Woodland carnivores are of all sizes, from insects such as beetles and lacewings to animals such as owls, shrews and foxes. Some carnivores feed on herbivores, some feed on the smaller carnivores, while some feed on both: a tawny owl will eat beetles and shrews as well as voles and mice. These food relationships between the different members of the community are known as food chains or food webs. All food chains start with plants. The links of the chain are formed by the herbivores that eat the plants and the carnivores that feed on the herbivores. There are more organisms at the base of the food chain than at the top; for example, there are many more green plants than carnivores in a community.
Another important section of the community is made up of the decomposers. They include the bacteria and fungi that live in the soil and feed on dead animals and plants. By doing this they break down the tissues of the dead organisms and release mineral salts into the soil.
What makes the links in a food chain?
