Question

about seventy percent of the earth’s surface is covered with water and is called the _______.
a) biosphere
b) lithosphere
c) hydrosphere
d) stratosphere

the part of the earth where life exists is the _______.
a) biodome
b) biosphere
c) hemisphere
d) atmosphere

a _______ can slope away from a land mass underwater for as much as 800 miles (1,287 km) in some areas of the world.
a) continental trench
b) continental ridge
c) continental shelf
d) continental drift

Explanation:

First Question:

• Option A (biosphere): The biosphere is the zone of life on Earth, including all living organisms and their environments, not specifically the water - covered part.
• Option B (lithosphere): The lithosphere is the rigid outer layer of the Earth, consisting of the crust and the upper mantle, mainly related to land and rock, not water.
• Option C (hydrosphere): The hydrosphere is defined as all the water on Earth's surface, including oceans, lakes, rivers, etc. Since about 70% of the Earth's surface is covered with water, this is the correct term.
• Option D (stratosphere): The stratosphere is a layer of the atmosphere, which is a gaseous layer above the Earth's surface, not related to water.

• Option A (biodome): A biodome is a man - made or natural enclosure that mimics an ecosystem, not the entire region where life exists on Earth.
• Option B (biosphere): The biosphere is the global sum of all ecosystems, which is the part of the Earth where life exists, including land, water, and air where living organisms can be found.
• Option C (hemisphere): A hemisphere is half of a sphere, usually referring to the Earth divided into northern and southern (or eastern and western) hemispheres, not related to the area of life.
• Option D (atmosphere): The atmosphere is the layer of gases surrounding the Earth, and while life interacts with the atmosphere, the atmosphere alone is not the part where life exists (life also exists in water and on land).

• Option A (continental trench): A continental trench is a deep depression in the ocean floor, usually associated with subduction zones, and it does not slope away from a land mass in the described way.
• Option B (continental ridge): A continental ridge is an underwater mountain range, not a feature that slopes away from a land mass.
• Option C (continental shelf): A continental shelf is the area of seabed around a large landmass where the sea is relatively shallow compared to the open ocean. It slopes away from the land mass underwater and can extend for a significant distance (up to 800 miles in some areas).
• Option D (continental drift): Continental drift is the theory that continents move over time, not a physical feature that slopes away from a land mass.

Answer:

C. hydrosphere

Second Question: