Question

proxy data a. provide climate data representing times when instruments were not available to measure them. b. are difficult to find because they occur only in very limited areas.c. come quality controlled instrument records.d. can only extend the temperature record back an additional 500 years.

Answer 1

Answer:a )provide climate data representing times when instruments were not available to measure them.

Explanation: Proxy data is the data collected by measuring it regarding the variations in the climate from the natural recorder . The records are based on the changes like the fossil pollen, tree rings etc. This information is collect from the past times.

Other given option are incorrect they don't give the correct definition of the proxy data.Therefore, the correct option is option(a).