Which statements help explain how Earth formed as part of the solar system? Select the two correct answers. (1 point) -The denser rocky material in the solar nebula stayed closer to the sun.
-Gaseous planets slowly changed to rocky planets after colliding with meteorites.
-Water and ammonia condensed from gases to ice particles.
-Very large asteroids broke apart to form rocky planets, including Earth.
-The accretion of cosmic dust formed the seeds of planets, including Earth

Which of the following statements is true about the relationship between genetic variation and natural selection? a. genetic variation must be present in a population before natural selection can act on it. b. genetic variation arises in a population as a result of natural selection. c. natural selection can act on a population whether there is genetic variation within the population or not. d. after natural selection acts on a population, the amount of genetic variation in the population always increases.