The fact that the Earth's orbit around the sun changes over time ...

[SO00]

The fact that the Earth's orbit around the sun changes over time is called ___________________ _. Fill in the blank(s) with the appropriate word(s).

Question 2

Finely laminated, alternating light and dark layers of sediment deposited in a glacial lake are known as
  glacial ___________________ _. Fill in the blank(s) with the appropriate word(s).

[lin77x]

Answer to Question 1

orbital eccentricity

Answer to Question 2

varves