I'd say that the answer is D. Speciation
Answer:
From left to right, they are Mercury, Venus, Earth, and Mars. Unlike the outer planets, which have many satellites, Mercury and Venus do not have moons, Earth has one, and Mars has two. Of course, the inner planets have shorter orbits around the Sun, and they all spin more slowly. The terrestrial planets are rich in heavier gases and gaseous compounds, such as carbon dioxide, nitrogen, oxygen, ozone, and argon. In contrast, the gas giant atmospheres are composed mostly of hydrogen and helium. The atmospheres of at least the inner planets have evolved since they formed.
Explanation: Hope this helps
D. single- and simple multi-celled organisms
Although more complex animals like invertebrates and multi-celled organisms began to appear, it was very late compared to the original, simpler organisms for which the Precambrian time is characterized by.
Answer:
The ratio of asteroid-A’s acceleration to asteroid-B’s acceleration is 37:7800.
Explanation:
Mass of asteroid-A = m =
Mass of asteroid-B = m' = 
As we know , Force = mass × Acceleration
1) Force on an asteroid-A
where , a is the acceleration due to force applied on asteroid-A
2) Force on an asteroid-B
where , a' is the acceleration due to the force applied on asteroid-B
Same force is exerted on the both the asteroids say F.
F = F'
The ratio of asteroid-A’s acceleration to asteroid-B’s acceleration is 37:7800.
