Answer:
Weather and erosion.
Explanation:
In Geography, weathering is the process of breaking down of rocks, minerals and soil as a result of contact with water, earth's atmosphere, acid, ice, plants and animals. The breaking up of the rocks by weathering weakens it and makes it susceptible to erosion.
Erosion in geography is the movement of rocks and sediments to another place by water, wind and ice.
For instance, In many parts of the Cross Timbers and Prairies ecoregion, the Brazos river has formed tall, steep cliffs in the rock along its banks through the processes of weathering and erosion.
<h2>Answer : By weighing the costs and benefits of an environmental issue
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Explanation :</h3>
The law makers usually conduct many studies before a law is imposed. They try to explore many other options available to the current environmental issue and then come to a conclusion to make a law.
They also weigh the cost aspect along with the benefit of the ongoing environmental issue. They try to come up with something which appears to be cost effective and result bearing.
<h2>Answer:</h2>
Compound. Option A is correct
<h2>Explanations:</h2>
When two or more different elements combines, a compound is formed. For instance, if carbon and oxygen combines, carbondioxide is formed according to the equation;

From the reaction, carbon and oxygen are the elements while carbondioxide is the compound. Hence we can conclude that a pure substance formed when two or more different elements combine called compound.