Olympiad Test: Natural Resources And Their Conservation -2 - Class 7 MCQ

Answer:
When it comes to activities that require a large quantity of water, the following options are the most suitable:
1. Bathing under a shower: Showering typically uses a significant amount of water due to the continuous flow. This activity requires a larger quantity of water compared to other options.
2. Bathing with a bucket of water: Although this option uses less water compared to showering, it still requires a relatively large quantity of water, especially if multiple buckets are used.
3. Washing a pair of shirts: Washing clothes can consume a substantial amount of water, especially if done manually. This activity may require a large quantity of water depending on the number of clothes being washed.
On the other hand, brushing your teeth does not require a large quantity of water. It is important to conserve water by turning off the tap while brushing.
To summarize, activities such as bathing under a shower, bathing with a bucket of water, and washing a pair of shirts require a larger quantity of water compared to brushing your teeth. It is important to be mindful of water usage and adopt practices that promote water conservation.

Green plants trap solar energy and synthesize their food, all animals directly or indirectly depends upon plants hence a food chain will not begin in the absence of green plants. 

Roots of trees normally bind the soil together.  

The correct statement is B: Forests do not influence the climate and water cycle. This statement is not correct because forests play a crucial role in influencing the climate and water cycle.
Here is a detailed explanation:
A: Plants and animals in a forest are dependent on one another.
- Forests are complex ecosystems where various plants and animals interact and depend on each other for survival.
- Plants provide food and shelter for animals, while animals help in pollination and seed dispersal for plants.
C: Forests protect the soil from erosion.
- Forests act as a natural barrier against wind and water erosion.
- The roots of trees help bind the soil together, preventing soil erosion and the loss of valuable topsoil.
D: Soil helps the forests to grow and regenerate.
- Soil provides essential nutrients and minerals to support the growth of trees and other vegetation in forests.
- It acts as a medium for roots to anchor and absorb water and nutrients necessary for plant growth.
B: Forests do not influence the climate and water cycle.
- This statement is incorrect.
- Forests play a vital role in regulating climate by absorbing carbon dioxide (a greenhouse gas) through photosynthesis and releasing oxygen.
- They also help in maintaining the water cycle by reducing evaporation and transpiration, increasing humidity, and promoting rainfall.
In conclusion, all the statements except B are correct. Forests are not only important for the interdependence of plants and animals, but they also protect the soil from erosion and have a significant influence on climate and the water cycle.

Inorganic Impurities Present in Sewage
There are various inorganic impurities that can be present in sewage. Among the options provided, the correct answer is C: metals. Here is a detailed explanation of the inorganic impurities present in sewage:
1. Metals:
- Sewage can contain various metals, both naturally occurring and those introduced through human activities. Some common metals found in sewage include lead, mercury, cadmium, copper, zinc, and chromium.
- These metals can enter the sewage system through industrial discharges, stormwater runoff, and domestic wastewater.
- Metals in sewage can have harmful effects on the environment and human health if not properly treated before discharge.
2. Urine:
- Urine is not considered an inorganic impurity but rather an organic component of wastewater.
- It contains various organic compounds, including urea, ammonia, and other nitrogenous compounds.
- While urine can contribute to the overall composition of sewage, it is not classified as an inorganic impurity.
3. Animal Dung:
- Animal dung is also not considered an inorganic impurity but rather an organic component of sewage.
- It contains organic matter, including feces and undigested food.
- While animal dung can be a source of organic pollutants in sewage, it is not classified as an inorganic impurity.
4. Vegetable Wastes:
- Vegetable wastes, similar to animal dung, are organic components of sewage.
- They consist of plant materials, such as leftover fruits, vegetables, and their peels.
- While vegetable wastes can contribute to the organic load of sewage, they are not classified as inorganic impurities.
In conclusion, among the given options, the inorganic impurities present in sewage are metals. It is important to properly treat sewage before its discharge to minimize the harmful effects of these impurities on the environment and public health.

The waste water coming from kitchen is called municipal waste water

Municipal waste water refers to the waste water that is generated from households, commercial establishments, and institutions such as schools and hospitals. It is commonly known as domestic waste water or sewage. Here are some key points to explain why the answer is option B:

• Definition: Municipal waste water is the term used to describe the waste water that is produced from various sources within a municipality or city.


• Source: The waste water from kitchens, bathrooms, toilets, and other household activities is considered part of the municipal waste water.


• Treatment: Municipal waste water goes through a treatment process in sewage treatment plants to remove contaminants and pollutants before it is discharged back into the environment.


• Composition: Kitchen waste water typically contains organic matter, food particles, grease, and detergents.


• Difference from other types of waste water: Municipal waste water is distinct from industrial waste water, which is generated from industrial processes, and rainwater, which is natural precipitation.

Therefore, the waste water coming from the kitchen is classified as municipal waste water.

In this question, we are given two statements related to the topic of wastewater management and treatment. We need to determine which statement is correct.

Statement 1: An underground pipe which carries away dirty drainage water is called a sewer.
Statement 2: The wastewater treatment plant is also called a sewage treatment plant.
Let's analyze each statement separately:
Statement 1: An underground pipe which carries away dirty drainage water is called a sewer.
This statement is correct. A sewer is a system of underground pipes that carries wastewater, including dirty drainage water, away from homes, buildings, and other structures to a treatment plant or a disposal point.
Statement 2: The wastewater treatment plant is also called a sewage treatment plant.
This statement is also correct. The terms "wastewater treatment plant" and "sewage treatment plant" are often used interchangeably to refer to a facility that processes and treats wastewater to remove contaminants before it is discharged back into the environment or reused for various purposes.
Therefore, both statements are correct, and the correct answer is option C: Both statements are correct.

Answer:
Introduction:
Waste water can contain various types of microbes, including bacteria, viruses, and parasites. These microbes can cause a range of diseases when they contaminate water sources and are ingested by humans.
Diseases caused by microbes in waste water:
The following diseases can be caused by microbes present in waste water:
1. Cholera:
- Cholera is an infectious disease caused by the bacterium Vibrio cholerae, which can be present in contaminated water sources.
- The bacterium is typically transmitted through the consumption of water or food that has been contaminated by fecal matter containing the bacteria.
- Cholera can cause severe diarrhea and dehydration, and if left untreated, it can be fatal.
2. Typhoid:
- Typhoid fever is caused by the bacterium Salmonella typhi, which can also be present in contaminated water sources.
- The bacterium is usually transmitted through the consumption of water or food that has been contaminated by fecal matter containing the bacteria.
- Typhoid fever can cause high fever, abdominal pain, and gastrointestinal symptoms, and it can be life-threatening if not treated properly.
3. Dysentery:
- Dysentery is a gastrointestinal infection caused by various types of bacteria, including Shigella and Campylobacter.
- These bacteria can be present in contaminated water sources and can be transmitted through the consumption of contaminated water or food.
- Dysentery can cause severe diarrhea, abdominal pain, and fever.
Conclusion:
All of the mentioned diseases, including cholera, typhoid, and dysentery, can be caused by microbes present in waste water. It is crucial to ensure proper sanitation and water treatment to prevent the spread of these diseases.

Organic Impurities in Sewage:

In sewage, organic impurities refer to the substances derived from living organisms that are present in the wastewater. These impurities can include:

1. Vegetable Wastes:

Vegetable wastes are a common organic impurity found in sewage. These include discarded food scraps, peels, and other plant-based materials.

2. Plastics:

Plastics, although not biodegradable, can also be present in sewage as an organic impurity. This includes items like plastic bags, bottles, and other plastic waste that may have been discarded in toilets or drains.

3. Other Organic Materials:

Aside from vegetable wastes and plastics, sewage may also contain other organic materials such as paper, cloth fibers, and other biodegradable substances.

4. Metals:

Metals, on the other hand, are not considered organic impurities. They are inorganic substances and are usually not present in significant amounts in sewage.

Conclusion:

Based on the given options, the correct answer is B: Vegetable wastes. Plastics and metals are not considered organic impurities in sewage.

Explanation:

Sewage is a mixture of wastewater from various sources, including households, industries, and commercial buildings. It contains a variety of substances, including organic matter, nutrients, and contaminants.

Nutrients present in sewage:

• Phosphorus: Sewage contains phosphorus, which is a vital nutrient for plants and organisms. Phosphorus is present in detergents, cleaning products, human waste, and food scraps that end up in sewage.


• Nitrogen: Nitrogen is another essential nutrient found in sewage. It is present in human waste, urine, and organic matter. Nitrogen is a key component of proteins and is necessary for plant growth.

Other substances in sewage:

• Chlorine: While chlorine may be present in sewage due to its use in disinfection processes, it is not considered a nutrient.

Therefore, the correct answer is (D) both (a) and (c) - phosphorus and nitrogen are present in sewage.