Answer the following question given this paragraph:   There are two common ways to measure pH. When only an approximate pH value is needed, an inexpensive test involves the use of acid-base indicators , which change color based on the relative acidity of the solution. One type of common indicator is litmus paper. For example, if a piece of litmus paper is dipped into an acidic solution (pH below ~4.5), it will turn red, and dipping it into a basic solution (pH above ~8.5) will turn it blue. Solutions of intermediate pH will result in various shades of purple. Because different indicators change color at different pH values, the use of multiple indicators can generally narrow down the possible pH of a solution to a range of about 0.5-1 pH units. Figure below shows the colors exhibited by various indicators at different pH values.   Q: How does litmus paper indicate the ph value of a solution?   Choices:  - by texture  - by shape  - by smell  - by color  A:
by color

Answer the following question given this paragraph:   The structure of heme (Figure 19.29), the iron-containing complex in hemoglobin, is very similar to that in chlorophyll. In hemoglobin, the red heme complex is bonded to a large protein molecule (globin) by the attachment of the protein to the heme ligand. Oxygen molecules are transported by hemoglobin in the blood by being bound to the iron center. When the hemoglobin loses its oxygen, the color changes to a bluish red. Hemoglobin will only transport oxygen if the iron is Fe2+; oxidation of the iron to Fe3+ prevents oxygen transport.   Q: When the hemoglobin loses its oxygen, it changes to what color?   Choices:  - purple red  - grayish red  - light pink  - bluish red  A:
bluish red

Answer the following question given this paragraph:   An underwater earthquake creates a tsunami this way: the movement of the crust displaces water. The displacement forms a set of waves. The waves travel at jet speed through the ocean. Since the waves have low amplitudes and long wavelengths, they are unnoticed in deep water. As the waves reach shore they compress. They are also pushed upward by the shore. For these reasons, tsunamis can grow to enormous wave heights. Tsunami waves can cause tremendous destruction and loss of life. Fortunately, few undersea earthquakes generate tsunamis.   Q: What type of earthquake creates a tsunami?   Choices:  - Tectonic  - collapse  - volcanic  - underwater  A:
underwater

Answer the following question given this paragraph:      Q: Photographs of the heat emitted by an object are called what?   Choices:  - radio images  - variable images  - cosmic images  - thermal images  A:

thermal images