Sara and Rajiv were making soil art and craft for their school project. Their grandma suggested that the soil from the bank of their village pond would be good for creating such models. Why was grandma's suggestion useful?

Once on a great sunny day, soil and trees were discussing with each other.

Said Soil to Tree, "Aren't you grateful to me?
I hold your roots firmly, so deep in the ground".
"No, no," said Tree.
"Surely you can see that the facts are actually the other way around. My roots keep you safe all night and all day.
If it wasn't for me, you'd soon be washed away".

"Stop fighting, you two" said an Owl sitting on the tree. "You both help each other, and you both help me."

Mention two ways in which Soil and Tree help each other. Also comment on the statement made by Owl "You both help me."  

Darjeeling is the northernmost district of the state of West Bengal in eastern India in the foothills of the Himalayas, popularly known as the 'Queen of the Hills'. Ramu lives in Darjeeling and does farming there. What method of farming should he use to prevent soil from being eroded?

Amit and his friends are having fun playing with soil in the field. Amit gathered some soil from the ground in a tiny bucket and brought it into his house. He then emptied the bucket in his compound. All the kids looked at the various things other than soil, like chocolate pieces, glass fragments, etc. When Amit's mother saw them playing with all these things, she warned them not to touch these soil pollutants as they can harm them and also contains fertilisers and pesticides. She also stated said, "Prolonged usage of pesticides is undesirable." Amit was taken aback by her response because he was aware that pesticides and fertilisers were used to increase crop yield.

a) "Prolonged use of pesticides is undesirable". Comment on this statement given by Amit's mother.

b) How is soil pollution caused? Discuss some measures of how soil pollution can be controlled.

Rohan and his friends play on a field nearby their house. Once, while playing a game during the rainy season, his friend discovered some little organisms in the ground. He showed them to Rohan. Rohan was startled and believed them to be snakes. All of them discussed it for sometime, but could not arrive at a conclusion. Rohan's father is a farmer, and Rohan thought of asking about this organism to him. They put the organism in a Polythene and brought it home to show it to Rohan's dad. All the kids went to Rohan's father and showed him the organism. Rohan's father told that it is not a snake, and these organisms are friendly creatures and are of great use to the farmers. 

Answer the following questions:

a) What is the name of this unknown creature?

b) Why during the rainy season, these unknown creatures come to the surface instead of hiding in their burrows?

c) Why these organisms are farmer-friendly?

Ranjini went outside with her father during the rainy season. While crossing a bridge, she saw that the river water appeared reddish-orange in colour. However, the water was practically translucent a few months earlier. She questioned her father about the reason for this colour change.
Her father explained that soil erosion is the reason for this colour change. He continued by saying that during rain, precipitation dissolves topsoil and carries it down rivers, changing the colour of the water and making it muddy.

Answer the following questions:

a) What is soil erosion?

b) Where will the soil erosion be maximum, in thick forests or bare lands?

A teacher was teaching students about the properties of soil in a classroom. Later, the teacher led all the students to the laboratory, where two beakers, A and B, were filled with different types of soil. The teacher called up two students near the table and instructed them to use measuring cylinders and funnel. The teacher then instructed them to fill one funnel with soil from beaker A and the other with soil from beaker B, and to place each funnel over the measuring cylinder. The teacher called up two more students and handed each one of them the two beakers filled with an equal amount of water, instructing them to slowly pour water into each funnel. After a while, the teacher took both measuring cylinders and measured the water collected after passing through each soil sample.

A. The water level in measuring cylinder B is less than the level in cylinder A. What does this indicate?

B. What property of soil is being measured here?

C. Write the formula to measure the percentage of water absorbed.

At Prasanna's house, they were digging a well. While the well was being dug, he noticed that there were different layers of soil, and each layer of soil has a different texture. He was surprised to find that only the top layer of soil had plants and trees, while the lower layers had no plants or roots. So he asked his elder brother why plants are only found in the upper layers of the soil and not in the lower layers. His brother responded that only the upper layer of soil contains all the substances required by plants.

From the above understanding, answer the following questions:

A. What is the name of the upper layer of the soil?

B. Give a reason why upper layer of soil most suited for plants?

C. Write the features of upper layer of the soil.