Essential Part 1
This type of reasoning question has an underlined word followed by four words. You have to select one word that is the necessary part of the underlined word.
A book cannot exist without pages.
If you do not have a crop, you have nothing to harvest.
A guitar cannot be made without strings, so strings are its essential part.
All shoes have sole. A shoe can be made without leather, and not all shoes have laces and shoes can be worn without socks.
When you purchase something, you acquire it. The purchase may be related to trade, profit or bank, but it can occur without them.
Essential Part 2
Essential Part 3
Essential Part 4