a) What are villi? What is their location and function? b) In places of hot climate it is advised that the outer walls of houses be painted white. Explain. c) Differentiate between weather and climate. d) Explain how soil is formed. e) Sketch the cross section of soil and label the various layers.
Answers
c) answer above
Answer:
a) The inner walls of the small intestine have thousands of finger like outgrowths called villi. each villus has a network of thin and small blood vessels. It is located in small intestine.
functions of villi
- it helps in the absorption of digested food material.
- it helps in the transportation of digested food material.
- it increases the surfaces areas of the small intestine for the absorption of digested food.
b) In places of hot climate, it is advised that the outer walls of house be painted white because white colour does not absorb any heat radiation from the sun which keep inside cool even if there is hot climate outside the house.
d) Soil is the thin layer of material covering the earth's surface and is formed from the weathering of rocks. ... Weathering of rocks takes place. Rock is broken down into small particles. These small particles mix with humus (organic matter) and form soil.
e)
● What are villi? What is their location and function?
The tiny projections on the inner surface of the small intestine which help in absorbing the digested food are called villi.
These helps to increase the surface area of intestinal walls.
● In places of hot climate it is advised that the outer walls of houses be painted white. Explain.
In places of hot climate, it is advised that the outer walls of house be painted white because white colour does not absorb any heat radiation from the sun which keep inside cool even if there is hot climate outside the house.
● Differentiate between weather and climate.
- Weather is day-to-day information of the changes in the atmospheric condition in any area.
~ Climate is statistical weather information that provides information about the average weather condition of a particular place over a long period.
- The changes in the weather condition can be observed very frequently.
~The changes in climate take a longer time to change.
- Weather forecasting is observed by the Meteorological Department
~Climatology is the scientific study of climate, which is described as the average of weather conditions over time.
- Weather is affected by temperature, pressure, humidity, cloudiness
~Atmospheric conditions at any location like humidity, temperature, the sunshine, wind, etc are affected by climate
● Explain how soil is formed.
Soil is the thin layer of material covering the earth’s surface and is formed from the weathering of rocks. It is made up mainly of mineral particles, organic materials, air, water and living organisms—all of which interact slowly yet constantly.
Soil formation is a two-step process:
- Weathering of rocks takes place. Rock is broken down into small particles.
- These small particles mix with humus (organic matter) and form soil.
● Sketch the cross section of soil and label the various layers.
A vertical section through different layers of the soil is called the soil profile. Each layer differs in feel (texture), colour, depth and chemical composition.
These layers are referred to as horizons.
The uppermost horizon is generally dark in colour as it is rich in humus and minerals. The humus makes the soil fertile and provides nutrients to growing plants. This layer is generally soft, porous and can retain more water. It is called the topsoil or the A-horizon.
The next layer has a lesser amount of humus but more minerals. This layer is generally harder and more compact and is called the B-horizon or the middle layer.
The third layer is the C-horizon, which is made up of small lumps of rocks with cracks and crevices.
Below this layer is the bedrock, which is hard and difficult to dig with a spade.
(pic in attachment)
