Answer:
4
Explanation:
Because the mean time taken to turn from blue/black to orange/brown (in minutes) was the shortest, showing that the rate of reaction was the highest.
Answer: 0.69 m/ mile.
Explanation:
The altitude gradient between two cities X and Y = 
Given: Two cities are separated by 200 miles.
City X has an altitude of 122 meters.
City Y has an altitude of 260 meters.
The altitude gradient between two cities X and Y =

Hence, the altitude gradient between the two cites = 0.69 m/ mile.
Answer: The “graying of America”
Explanation: Just took the test
Biotic and living are the same thing, abiotic would be non-living
The answer is D because bacteria is one or more cells.