Answer:
Controlled variables include time, temperature, volume of solution being tested, and volume and concentration of reagent (Benedicts or iodine) used. Three unknown solutions will be tested for the concentration of reducing sugars using Benedict's solution.
Explanation:
1. C
2. B
3. C
4. A
5. D
6. B
7. D
8. D
9. C
10. A
Answer:
Precambrian era is the longest era in the Earth's history. It began 4600 million years ago and ended about 540 million years ago.
Explanation: