Class 9 Oceans and Life Mock Test (CBSE)

Topics in Oceans and Life

• Ocean relief
• Waves
• Tides: spring and neap tides
• Ocean currents
• Cyclones and tsunamis: early warning systems
• Marine resources and their significance
• Blue economy
• Maritime zones
• International maritime rules and regulations

Oceans and Life practice questions with answers

1. Q1Assertion and reason·1 mark
   Assertion (A): Cold ocean currents make the coastal regions of some deserts, such as the Atacama, very dry. Reason (R): Cold currents increase rainfall over the coast because they warm the air above them.

   1. (a)Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
   2. (b)Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
   3. (c)Assertion (A) is true but Reason (R) is false.
   4. (d)Assertion (A) is false but Reason (R) is true.
   Show answer and step marks

   1. Correct option: (c) Assertion (A) is true but Reason (R) is false.+1

   Answer: (c)
2. Q2Multiple choice·1 mark
   What is the primary driving force for the generation of surface ocean currents?

   1. (a)Lunar gravitational pull
   2. (b)Prevailing planetary winds
   3. (c)Earth's magnetic field
   4. (d)Geothermal heat from the ocean floor
   Show answer and step marks

   1. Correct option: (b) Prevailing planetary winds+1

   Answer: (b)
3. Q3Multiple choice·1 mark
   Which of the following processes is primarily responsible for the continuous movement of water between the oceans, atmosphere, and land?

   1. (a)Deep ocean trench formation
   2. (b)The hydrological cycle
   3. (c)Coriolis deflection
   4. (d)Salination of deep water
   Show answer and step marks

   1. Correct option: (b) The hydrological cycle+1

   Answer: (b)
4. Q4Short answer·3 marks
   Explain any three major human activities that pose a serious threat to marine ecosystems and ocean life.
   Show answer and step marks

   1. First activity, any one of: plastic and chemical pollution from land, which harms or kills marine organisms; oil spills from ships and offshore drilling; overfishing and destructive methods such as bottom trawling, which deplete fish stocks and disturb food webs; carbon emissions causing ocean warming and acidification, which bleach and damage coral reefs; sewage and fertiliser run-off, which create oxygen-poor dead zones; clearing mangroves and reefs for coastal development; or any other valid human activity, explained.+1
   2. Second activity, a different one from the same list.+1
   3. Third activity, a different one from the same list.+1

   Answer: Any three of: plastic and chemical pollution harming marine life; oil spills; overfishing and destructive fishing depleting fish stocks; carbon emissions warming and acidifying the oceans and damaging coral reefs; sewage and fertiliser run-off creating dead zones; destruction of mangroves and reefs for coastal development.

More Class 9 Social Science (SST) mock tests