Which of the following layers of the Earth is unique among the terrestrial planets?
A) hydrosphere
B) ionosphere
C) mantle
D) crust
E) core
Question 2
What are constellations?
A) groups of galaxies gravitationally bound and close together in the sky
B) groups of stars making an apparent pattern in the celestial sphere
C) groups of stars gravitationally bound and appearing close together in the sky
D) ancient story boards, useless to modern astronomers
E) apparent groupings of stars and planets visible on a given evening
Annual net primary productivity on Earth.
Possible Earth 5 billion years from now
A Piece of Mars on Earth
In the Tai Forest a female chimp demonstrates a skill once thought to be unique to humans. Here she
The three layers of the skin.
Derivatives of Vertebrate Germ Layers