01 In ocean floor mapping, what does a bathymetric map show most clearly?0 reads0 helpful★ – (0)
A Depth and ocean floor relief B Only the colour of seawater C Only coastal population D Political division of oceans
Answer and explanation Correct answer: A . Depth and ocean floor relief
Explanation: A bathymetric map shows depth and shape of the sea floor. Exam tip: treat it as a topographic map of the ocean.
02 If the return time of a sound wave is longer in echo sounding, what does it mean?0 reads0 helpful★ – (0)
A The sea is shallower B The sea floor is deeper C The sound wave has stopped D The ship is near the coast
Answer and explanation Correct answer: B . The sea floor is deeper
Explanation: Longer time means the sound travelled a greater distance. Exam tip: remember the direct relation between time and depth.
03 What is indicated by closely spaced isobaths about the ocean floor?0 reads0 helpful★ – (0)
A The floor is completely flat B There is no change in depth C The slope is steep D The sea floor is dry
Answer and explanation Correct answer: C . The slope is steep
Explanation: Closely spaced isobaths show a rapid depth change over a short distance. Exam tip: link close lines with steep slope.
04 Why is multibeam sonar considered better than simple sonar in ocean floor mapping?0 reads0 helpful★ – (0)
A It makes seawater fresh B It measures only one point C It does not use sound D It maps a wide strip of relief at once
Answer and explanation Correct answer: D . It maps a wide strip of relief at once
Explanation: Multibeam sonar uses many sound beams to collect data over a wider area. Exam tip: treat it as a detailed mapping technique.
05 Which statement correctly identifies the continental shelf?0 reads0 helpful★ – (0)
A A shallow submerged continental part near the coast B The deepest trench in the middle of ocean C A high volcanic mountain on the sea floor D A very flat plain of the deep ocean
Answer and explanation Correct answer: A . A shallow submerged continental part near the coast
Explanation: The continental shelf is a shallow resource-rich zone near the coast. Exam tip: connect it with coast and resources.
06 Why is mapping the continental slope important?0 reads0 helpful★ – (0)
A Because it only shows ocean colour B Because it shows the change from shelf to deep ocean basin C Because it closes all oceans D Because it shows atmospheric layers
Answer and explanation Correct answer: B . Because it shows the change from shelf to deep ocean basin
Explanation: The continental slope is the transition from shallow shelf to deep basin. Exam tip: remember slope after shelf in the sequence.
07 Which sign is most useful for identifying abyssal plains on the ocean floor?0 reads0 helpful★ – (0)
A Very shallow coastal water B Steep mountain slope C Broad flat area in deep ocean D Floating ice on the surface
Answer and explanation Correct answer: C . Broad flat area in deep ocean
Explanation: Abyssal plains are broad low-slope parts of the deep ocean. Exam tip: understand them as flat plains of the deep sea.
08 Why is mapping mid-oceanic ridges useful for plate tectonics?0 reads0 helpful★ – (0)
A Because they reduce seawater temperature B Because they show coastal population C Because they are only fishing areas D Because they are linked with plate spreading zones
Answer and explanation Correct answer: D . Because they are linked with plate spreading zones
Explanation: Mid-oceanic ridges are often linked with sea-floor spreading. Exam tip: connect them with plate boundaries.
09 Mapping an oceanic trench helps understand which geological process?0 reads0 helpful★ – (0)
A Subduction B Evaporation C Glacial deposition D Formation of sand dunes
Answer and explanation Correct answer: A . Subduction
Explanation: Oceanic trenches are generally linked with subduction zones. Exam tip: remember trenches with convergent plate boundaries.
10 How does satellite altimetry help in ocean floor mapping?0 reads0 helpful★ – (0)
A It directly enters the sea and cuts rocks B It estimates floor relief from small sea-surface height variations C It only counts ships D It makes seawater solid
Answer and explanation Correct answer: B . It estimates floor relief from small sea-surface height variations
Explanation: Small variations in sea surface can indicate large features below. Exam tip: understand it as an indirect mapping method.
11 How is a submarine canyon identified in ocean floor mapping?0 reads0 helpful★ – (0)
A A round mountain in deep sea B A flat plain away from coast C A deep cut valley on the sea floor D An oil layer on sea surface
Answer and explanation Correct answer: C . A deep cut valley on the sea floor
Explanation: A submarine canyon is a deep valley-like cut on the sea floor. Exam tip: understand it as a submerged valley.
12 What is the main difference between a seamount and a guyot?0 reads0 helpful★ – (0)
A A guyot has a flat top, whereas a seamount generally has a conical or irregular summit B A guyot forms in an ocean trench, whereas a seamount occurs only near a continental coast C A guyot is made of sedimentary rocks, whereas a seamount is made only of granite D A guyot lies on the ocean floor, whereas a seamount always rises above sea level
Answer and explanation Correct answer: A . A guyot has a flat top, whereas a seamount generally has a conical or irregular summit
Explanation: A guyot is essentially a submerged volcanic seamount whose summit has been flattened by wave action and erosion. An ordinary seamount commonly has a conical, rounded, or irregular summit. Option D is incorrect because a seamount does not reach sea level; if it rises above the surface, it becomes an island. Exam tip: the key identifying feature of a guyot is its flat top.
13 What is the main advantage of a digital model of the ocean floor?0 reads0 helpful★ – (0)
A It helps understand relief in three-dimensional form B Ocean salt disappears C All ships start moving automatically D Ocean boundaries disappear
Answer and explanation Correct answer: A . It helps understand relief in three-dimensional form
Explanation: Digital models visually show depth height and slope of the sea floor. Exam tip: treat models as tools of analysis.
14 What was a limitation of the old rope-and-weight method in ocean floor mapping?0 reads0 helpful★ – (0)
A It made very fast and complete regional maps B It gave only point depth and was slow C It was operated by satellites D It automatically gave sea-floor images
Answer and explanation Correct answer: B . It gave only point depth and was slow
Explanation: The rope-and-weight method was slow and limited to point measurements. Exam tip: see sonar as progress over it.
15 Why is a profile line used in making an ocean floor profile?0 reads0 helpful★ – (0)
A To know cloud direction above the ocean B To count coastal cities C To show depth changes along a selected line D To decide the colour of the ocean
Answer and explanation Correct answer: C . To show depth changes along a selected line
Explanation: A profile line helps create a cut-view of the ocean floor. Exam tip: connect it with cross section.
16 Mapping sediment thickness on the ocean floor can indicate what information?0 reads0 helpful★ – (0)
A Language of fish in the sea B Names of coastal cities C Daily colour of the sea D Geological history and nature of deposition
Answer and explanation Correct answer: D . Geological history and nature of deposition
Explanation: Sediment thickness gives clues about deposition and past environment. Exam tip: treat sediments as records of the sea floor.
17 Why are depth data checked repeatedly in ocean floor mapping?0 reads0 helpful★ – (0)
A To reduce errors and improve accuracy B To heat the ocean more C To change country borders on maps D To stop sound waves
Answer and explanation Correct answer: A . To reduce errors and improve accuracy
Explanation: Repeated checking detects wrong readings and instrument errors. Exam tip: link quality control with accurate maps.
18 Why is reading the map legend necessary in ocean floor mapping?0 reads0 helpful★ – (0)
A Because it explains the meaning of colours and depth symbols B Because the legend changes weather C Because the legend dries the ocean D Because the legend is only decoration
Answer and explanation Correct answer: B . Because the legend changes weather
Explanation: A map legend helps interpret colours and symbols. Exam tip: always check the legend in map questions.
19 If a bathymetric map shows a sudden large increase in depth, which feature is likely?0 reads0 helpful★ – (0)
A Continental shelf B Coastal lagoon C Continental slope or trench D Sea beach
Answer and explanation Correct answer: C . Continental slope or trench
Explanation: A sudden depth increase may indicate a steep slope or trench. Exam tip: identify features from depth change.
20 What is the main difference between ship-based survey and satellite method in ocean floor mapping?0 reads0 helpful★ – (0)
A Both only count population B Ship method directly measures depth while satellite gives indirect estimates C Satellite drops a rope into the sea D Ships never use sound
Answer and explanation Correct answer: B . Ship method directly measures depth while satellite gives indirect estimates
Explanation: Ships directly measure with sonar while satellites estimate from surface signals. Exam tip: separate direct and indirect methods.
21 Why is knowing sea-floor irregularity important for laying submarine cables?0 reads0 helpful★ – (0)
A Because safe routes can be selected B Because fish colours change C Because rainfall stops D Because the ocean dries
Answer and explanation Correct answer: A . Because safe routes can be selected
Explanation: Knowledge of trenches slopes and obstacles reduces cable risk. Exam tip: remember practical uses of mapping.
22 How are depth and marine habitats related in ocean floor mapping?0 reads0 helpful★ – (0)
A The same habitat occurs at every depth B Depth affects light pressure and living conditions C Depth has no relation with life D Life exists only on coasts
Answer and explanation Correct answer: B . Depth affects light pressure and living conditions
Explanation: Changing depth affects light pressure and thermal conditions. Exam tip: connect depth with habitat zones.
23 Which information from ocean floor mapping is useful in tsunami modelling?0 reads0 helpful★ – (0)
A Taste of seawater B Number of seabirds C Coastal depth and sea-floor slope D Colour of ships
Answer and explanation Correct answer: C . Coastal depth and sea-floor slope
Explanation: Coastal depth and slope can affect wave height and speed. Exam tip: remember the role of bathymetry in disaster studies.
24 How can a continental rise be identified?0 reads0 helpful★ – (0)
A By dry land above the shelf B By clouds on sea surface C Only by fishing D By a gentle sedimented zone below the continental slope
Answer and explanation Correct answer: D . By a gentle sedimented zone below the continental slope
Explanation: Continental rise forms due to sediments below the continental slope. Exam tip: remember the sequence shelf slope rise.
25 Which information is primary for exploring marine minerals through ocean floor mapping?0 reads0 helpful★ – (0)
A Relief and geological structure B Sea songs C Age of sailors D Coastal language
Answer and explanation Correct answer: A . Relief and geological structure
Explanation: Relief and geological structure help identify mineral zones. Exam tip: connect resource exploration with sea-floor mapping.