All of the following fish choices have high levels of the toxin mentioned in the video except for
1. swordfish
2. salmon
3. tilefish, or golden bass
4. shark

Option 2, Salmon

Explanation:

Large fishes such as shark and sword fish have higher level of mercury. This fact can be explained by the concept of bio magnification in which an individual lying at a higher trophic level in a food chain gets accumulated toxin and hence possess the highest amount of toxin in a given food chain. Small fish such as salmon will have the lowest amount of mercury as they lie at the lower level of a food chain and hence possess a small amount of toxin

the index of refraction of the second medium is higher. i just took the test trust me !