A two-column proof contains a table with a logical series
of statements and reasons that reach a conclusion. It is commonly present
in geometry. Two column proofs always have two columns: statements and reasons.
The other choices don’t fit in the definition of two column proof.
Dune deflation hollows are where wind has removed sand down to a level where a layer of particles too heavy for the wind to move (an armoured surface) stabilises the sand and prevents the surface being lowered further.
A crevasse is a deep, wedge-shaped opening in a moving mass of ice called a glacier. Crevasses usually form in the top 50 meters (160 feet) of a glacier, where the ice is brittle.
a mass of rocks and sediment carried down and deposited by a glacier, typically as ridges at its edges or extremity.
Today the world's population is 7.5 billion. The world's population is changing because of the natural increase rate. The natural increase rate is the crude birth rate minus the crude death rate. Since the crude birth rate is higher than the crude death rate today, this would lead to a higher natural increase rate.
