There was no life on Earth for the first billion years because the atmosphere was not suitable for life. Earth's first atmosphere had lots of water vapor but had almost no oxygen. Later, frequent volcanic eruptions put several different gases into the air.
Answers: 1 .The difference in the brightness of two stars with the same surface temperature is attributable to their sizes.( last choice)
2.Most responsible for the formation of a star is gravitational force.(second choice )
3. Blue ( last choice)
4.
A spinning neutron star that appears to give off radio wave pulses is called a pulsar ( third choice)
5.Greater redshifts in the spectra of galaxies indicate faster speeds ( first choice)
Grass would be the correct answer because grass seeds can float in the air. It grows everywhere and at any weather.
B. sodium and chloride because an ionic bond only form between oppositely charged particles.
Answer:
C.
Explanation:
Food chains focus on one set of organisms and their predators/prey, while food webs show multiple for each. Hope this helps. :)
