Compared to the bedrock layers above and below the rock ledge shown at the waterfall, the characteristic that is primarily responsible for the existence of the rock ledge is its greater
1.
resistance to weathering
2.
abundance of fossils
3.
thickness
4.
age

The correct answer is option 1, that is, resistance to weathering.

Explanation:

After examining the picture of the waterfall, the feature, which is mainly accountable for the presence of the rock ledge is its greater resistance to weathering. Some kinds of rocks are very resistant to weathering. The igneous rocks, mainly the intrusive rocks like granite, weather gradually as it is tough for water to get inside them. The rocks behave distinctly to weathering because of the differences in the structure of mineral and its content.

the correct option is c.

isotopes refers to different forms of the same element with the same atomic number but different mass number as a result of difference in their neutron numbers. isotopes have different relative atomic mass but share the same chemical properties.

if you're asking what comes out, it's steam.