What is the current axial tilt of the earth?
A) 24 degrees B) 45 degrees C) 21.5 degrees D) 23.5 degrees
Question 2
The Kurgans, identified as the first Proto-Indo-European speakers by archaeologist Marija Gimbutas
A) conquered much of East Asia several thousand years ago.
B) were a Germanic tribe that invaded England.
C) were herders from the steppes of today's Russia and Kazakhstan.
D) preserved Basque in present-day Spain.
E) were the earliest speakers of Sino-Caucasian, which they diffused through conquest.
Rivers on Mars and Earth
Concentric double-pipe heat exchanger for co-current flow
Earth’s Spheres
Geothermal energy and powers Earth’s systems
The rock cycle and the Earth’s physical environment
Convert from degrees to radians