Science Olympiad Test: Our Environment- 1 - Class 10 MCQ

Biodegradable items are those, which can be degraded by biological agencies like detrivores. These organisms feed on the dead and decaying matter and convert them into minerals and return those minerals back to the environment, thus completing the cycle of nutrients. Non-biodegradable items are those which cannot be acted upon by detrivores. Thus, such items cannot be degraded or decomposed. In a way, they are a permanent addition to the environment and cannot be done away with. For example, polythene, thermosetting plastics like bakelite, insecticides like DDT, detergent, PVC, etc. These items cannot be degraded biologically.

The sun is considered the primary energy source since it is the source of nearly all the earth’s energy.

• Plants produce food using sunlight, and the food we get from plants and animals also has its primary sunlight source.
• The fossil fuels we use in our everyday lives come from dead plants and animals that have their origins as solar energy again.
• It is the primary source of energy for the earth.
• With the help of solar energy, all green plants(producers) produce food by the process of photosynthesis.
• In turn, animals eat plants and use that same chemical energy for all their activities.

Lotic water systems are bodies of water that are flowing continuously, ranging from torrential rapids to slow-moving backwaters. Rivers, Streams, and springs are prime examples of lotic ecosystems.

Excessive killing of lions resulted in an increase in the number of herbivores, which in turn consumed all the vegetation. Hence, the Sahara Desert was formed.

The Decomposition of domestic wastes under the natural process is called Biodegradable Pollution. These substances can be broken down into simpler, harmless substances by bacterial action and other natural means of degradation over a due course of time.

An artificial ecosystem is a man-made system where there is the interaction among plants, animals, and people living in an area together with their surroundings.
Examples are crop fields, and aquariums.

• Grasshopper is a primary consumer because it feeds on grass. If a grasshopper is getting eaten by a frog. The frog will be the secondary consumer.
• Consumers are organisms that obtain energy by feeding on other organisms. In the food chain, heterotrophs are primary, secondary and tertiary consumers. An Example of consumers is animals.

Zooplankton are herbivorous micro-organisms such as protozoa that are found in water bodies. They depend upon producers for food and hence are not producers.

Plastic is a non-biodegradable substance, and hence it cannot be decomposed by composting.

Reymond Lindeman gave ten percent of energy transfer law or Lindeman’s trophic efficiency rule in food chains. The 10 percent energy is transferred from one trophic level to the next successive trophic level according to this rule. During energy transfer and respiration, the majority of the energy is lost. The maximum energy is in the first trophic stage.