Question #3
what were the two most important sources of the heat that melted the entire early earth, allowing materials of different density to differentiate?
heat released by collision processes during accretion, and heat from decay of radioactive elements
heat from fires on the early earth, and heat from the sun
heat from decay of radioactive elements, and heat from the sun
heat from the sun, and heat released by volcanic eruptions
heat from fires on the early earth, and heat released by volcanic eruptions
question #4
which of the following statements is true regarding spacecraft trajectories near planets at orbital speeds above the escape velocity?
the spacecraft will be captured by the planet.
the spacecraft will proceed in a straight line and not be deflected.
the spacecraft will always have the same overall speed before the encounter as after it.
this is impossible; spacecraft must always stay in orbit and can never exceed escape velocity.
the spacecraft can either gain or lose orbital speed during the encounter depending on the exact orbit.

1. in 1492, spain expelled after being under their rule for centuries. a. the portuguese b. the basques c. the castilians d. the moors 2. an important cultural center during the renaissance was the city of a. milan b. bologna c. florence d. naples 3. what is the connection between the minoan civilization and a volcanic eruption on thera? a. the earthquake happened a century before the collapse of the civilization. b. the earthquake created a graben. c. the earthquake caused the collapse of the civilization. d. the earthquake caused a volcanic eruption. 4. throughout history, other cultures influenced greece through a. military conquest b. shared ideals c. trade agreements 5. geographically, spain is isolated from the rest of europe by a. portugal b. the atlantic ocean c. the pyrenees mountains d. narrow coastal plains 6. most of central spain is known as the meseta, which is the spanish word for a. mountains b. plateau c. peninsula d. plains 7. for the people of ancient greece, the  iliad, and the  odyssey  a. copied western ideals b. were not popular c. presented community standards d. were children’s poems\ 8. western cultures got many of their ideas about from ancient greece. a. warfare b. democracy c. education d. agriculture 9. how is greece’s natural vegetation similar to that of other mediterranean countries? a. it has been damaged by forest fires. b. it is mainly deciduous forests. c. it grows rapidly in the wet climate. d. it has been reduced to scrub vegetation by overgrazing. 10. what is the most productive agricultural area in italy? a. the alps b. the po valley c. southern italy d. the apennines 11. many factories in northern italy use for energy. a. coal b. hydroelectricity c. nuclear energy d. natural gas 12. what major landform covers much of italy? a. the apennines b. the po river valley c. the alps

The volume of the triangular prom is 54 cubic units

Where does the availability of water pose the greatest problem