How do scientists use lake sediments to study past climates? ...

[ahriuashd]

How do scientists use lake sediments to study past climates?
 
  A) Lake sediments contain organic materials that can be identified to species and radiocarbon dated, thereby giving insight into past plant communities and related climatic conditions.
  B) Isotopic analysis of the relative proportions of 18O to 16O enable determination of evaporation rates from ancient lakes.
  C) During warmer conditions, lake sediments form wider rings, whereas in cooler conditions, these rings are narrower.
  D) The amount and type of pollen in lake sediments is an indication of the macrovertebrate assemblages that dominated an area.
  E) Lake sediment analysis is used to determine which fish species have persisted in a particular lake over long periods of time.

Question 2

The 10C (50F) isotherm for July is used as the environmental criteria to define
 
  A) the Antarctic convergence.
  B) periglacial regions.
  C) the Arctic region.
  D) the Antarctic region.
  E) the extent of Pleistocene glaciation.

[dawsa925]

Answer to Question 1

A

Answer to Question 2

C

[ahriuashd]

TYSM

[shewald78]

Excellent