Question 1
- State two forces that shape the surface of the earth.
- State three characteristics of the crust.
Answer
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- Centrifugal flinging force that causes the bulge at the equator
- Gravitational – pulls towards the centre causing the rounding effect -
- Average thickness 16 – 24km
- Made up of two parts. the outer and inner crust
- The outer crust made of Silica and aluminium (SIAL)
- The inner crust made of SIMA
Question 2
- Distinguish between a coast and a shore.
- State three conditions necessary for the formation of a spit.
Answer
- - A coast is a strip of land that is bordering the sea while a shore is the point along the coast that lies between the lowest water tide and the highest point reached by waves.
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- Relatively shallow and sheltered water
- Availability of a lot of load
- A long one ward shore drift must occur
- A gently sloping shoreline
Question 3
- State three ideal conditions for the formation of an artesian well
- Give two ways in which underground water may reach the earth surface.
Answer
-
- the aquifer must outcrop in a region which is a source of water
- the aquifer must did from a region of water intake to form a broad syncline
- the aquifer must lie between impermeable rocks so as to retain water
-
- through spring / wells / seepage
- through capillary action / trangiration
Question 4
- What is a lake
- Give 3 reasons why most of the Rift Valley lakes are alkaline
Answer
- A lake is an accumulation of water in a wide hollow or depression / it is an extensive hollow in the earth’s surface which contains water
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- Most lakes have no outlets
- The area experiences volcanic eruptions.
- Most rivers that drain into them are salty
- High rate evaporation in the region.
Question 5
- Highlight three natural causes of climate change
- State two effects of climate change on the physical environment
Answer
-
- Variation in the earth’s orbital characteristics
- Variation in solar output
- Variation in CO2 in atmosphere. -
- Causes increase in atmospheric
- Causes changes in rainfall pattern e.g. flooding , drought
- Causes change in season as pattern /air masses