7TH GRADE SCIENCE EARTH'S CHANGING SURFACE

In the Chihuahuan Desert Ecoregion of Texas, rocks break down because high winds blow sand over them wearing the surface away a little at a time. The process of slow wearing down due to being blasted by particles is an example of:

• mechanical weathering

• chemical weathering

• erosion

• deposition

2. The picture above represents a watershed. Why could a chemical spill that occurs in the hills above the river be a threat to ocean life?

• The chemicals could evaporate and blow into the ocean.

• The chemicals could be absorbed by plants and enter the food supply.

• The chemicals could wash into the streams and be carried by the river to the ocean.

• The chemicals could be stored in aquifers between layers of rock.

3. After a fire in the Piney Woods ecoregion, the native plants were essentially wiped out. Which of the following describes the process that happens as those plants start to regrow?

• Primary succession

• Secondary succession

• An ecosystem

• A climax community

Water that collects within rock layers beneath Earth's surface is called _____.

• surface water

• a pond

• groundwater

• . a lake

4. Beaches in the Gulf Coast were deeply affected by Hurricane Ike in 2008. Estimates report that over 100 million cubic yards of sand were removed due to the hurricane’s crashing waves and 15 foot storm surge. The process that can carry sand away from a beach is known as

• Mechanical Weathering

• Erosion

• Deposition

• Chemical Weathering

How do pioneer species prepare an area for other living things?

• By replacing other species

• By creating soil for other species

• By protecting other species from harm

• By stopping the process of succession

Sand dunes are formed when sand particles get dropped off in a pile. The process by which the sand particles are dropped to make the sand dune is known as:

• Mechanical weathering

• Chemical weathering

• Erosion

• Deposition

The Edwards Plateau Ecoregion of Texas is known for its extensive underground caves. The caves formed because of water reacting with the limestone underground and dissolving it. This process is known as

• deposition.

• chemical weathering.

• mechanical weathering.

• abrasion.

The physical environment of an area changes over many years following an explosive volcanic eruption. The process of ecological succession will be complete when _____

• the area can no longer support living things.

• another volcanic eruption occurs.

• the first populations of plants move into the area.

• the ecosystem reaches equilibrium and is occupied by stable populations.

Which of the following statements correctly describes how a delta forms?

• Sediment is carried downstream in a process known as weathering, and it is dropped off in a process known as erosion.

• Sediment is carried downstream in a process known as erosion, and it is dropped off in a process known as weathering.

• Sediment is carried downstream in a process known as deposition, and it is dropped off in a process known as erosion.

• Sediment is carried downstream in a process known as erosion, and it is dropped off in a process known as deposition.