I believe your answer is 23.
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1. Has 4 sig figs, all non zeros are significant
2. 3 sig figs trailing zero after a decimal
3. 3 sig figs
Answer is: acid-base indicator or pH indicators.
Acid-base indicators are usually weak acids or bases and they are chemical<span> detectors for hydrogen or hydronium cations.</span>
Example for acid-base indicator is phenolphthalein (molecular formula C₂₀H₁₄O₄). Phenolphthalein is <span>colorless in </span>acidic<span> solutions and pink in </span>basic<span> solutions.
Another example is m</span><span>ethyl orange. It is red colour in acidic solutions and yellow colour in basic solutions.</span>
Answer:
doesnt increase air pollution. fertilizers leak into the waters when it rains
