please help with the Astronomy question 1-7 and explain why, thank you
1. America's first manned spacecraft:
A. Apollo B. Gemini
C. Mercury D. Space Shuttle
E. Sputnik
2. Greenhouse gas most responsible for Earth's overall surface temperature:
A. Carbon dioxide
B. Chlorofluorocarbons (CFCs)
C. Methane
D. Nitrous oxide
E. Water vapor
3. Consider a world with 1/10th the mass and half the radius of Earth. Its average density is how many times that of Earth?
A. 0.1
B. 0.4
C. 0.45
D. 0.8
E. 50
4. Ruled out because the Earth and the Moon share the same mantle material:
A. Sister theory
B. Capture theory
C. Daughter theory
D. Impact theory
5. Discovered the rings of Saturn and Saturn's large moon Titan:
A. Cassini
B. Galileo
C. Herschel
D. Huygens
E. Newton
6. Earth's deepest fluid layer:
A. Inner core
B. Outer core
C. Lower mantle
D. Asthenosphere
E. Lithosphere
7. Least likely explanation for Venus's slow, backward rotation:
A. Always rotated that way
B. Atmospheric drag
C. Collision with another planet
D. Once closer to the sun and tidally locked