Answer:
b. during the final stages of cooling, a lava flow contracts, forming tall polygonal fractures
Explanation:
The columnar joints are very interesting and attractive for the eye geological features. They are not very common feature which makes them even more interesting. Some of them have been covered by sediments so they are hidden below the surface, but some have remained above the surface, sticking out as the erosion acts much slower on them than the surrounding area. They form when the lava cools off very quickly at its final stages, thus starting to contract, and instead of being smooth, they become polygonal fractures that are very tall.
<span>The answer is B. It can be converted from high to low voltage and vice versa using transformers. That is why high voltages (tens or hundreds of kilovolts) is used to efficiently transfer electricity for large distances and then converted to 110-240V.
The answer can also be derived by elimination. [A] is not right because battery provides only Direct Current (DC). [C] is not right because high voltages are used for AC (from 110V to hundreds of kilovolts). [D] is not right because as the name Alternating Current suggests, the current is alternating in its direction. [E] is not right because DC was the first type of current invented.</span>
1. I think is letter b.
2. I thinks it's letter c.
It's D. Gravity holds everything in place
