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.
<u>Answer:</u>
Approximately, the oldest stromatolites are 3.6 billion years old on earth.
<u>Explanation:</u>
- Stromatolites is not only oldest earths fossil but conspiracy in that they are singular visual portal in deep time on earth.
- It is defined as laminated accumulation structure that is they stick up above sea floor .
- Stromatolite buildings includes oldest fossils which are 3.5 billions old when the earth were too unfriendly to support life.
- The study of fossil age, evolutionary, method of formation are known as paleontology.
- These specimens are considered as old fossils which are around 3.4 to 4.1 billions years old.
Answer:
blood consists of plasma, red blood cells, white blood cells, and platelets
Explanation: