instruction:
Given a scientific passage and an answer, generate a question for the given answer.
question:
Passage: Not all wetlands are alike, as you can see from Figure below . Wetlands vary in how wet they are and how much of the year they are soaked. Wetlands also vary in the kinds of plants that live in them. This depends mostly on the climate where the wetland is found. Types of wetlands include marshes, swamps, and bogs. Answer: wetlands
answer:
Marshes, swamps, and bogs are types of what?

question:
Passage: Substances may be either elements or pure compounds. They may also be solid, liquid, or gas. Some of the elements (such as silver) exist in the solid form. Other elements (mercury) exist as liquids at room temperature. Elements such as helium and radon exist as gases at room temperature. A compound such as water will take the form of a solid, a liquid, or a gas, depending upon the temperature. Answer: pure compounds
answer:
Substances may be either elements or what?

question:
Passage: There are 20 amino acids that make up proteins. With three bases per codon, there are 64 possible codons. This is more than enough to code for the 20 amino acids plus start and stop signals. You can see how to translate the genetic code in Figure below . Start at the center of the chart for the first base of each three-base codon. Then work your way out from the center for the second and third bases. Answer: 20
answer:
How many different amino acids make up proteins.