A large asteroid or comet impacted the earth.
b is the correct answer. hope this helps
Answer:
Let's consider that the allele 'B' is for Black hair colour and it is dominant. Let's consider that the allele for red hair colour is b.
Let's consider the allele for lacking horns or polles is 'P' and it is dominant. The allele for having horns is 'p' and it is recessive.
When two heterozygous black, lacking horns (BbPp) are crossed, the results will have the probability of 9 black/polled : 3 black/horned : 3 red/polled : 1 red/horned organisms.
Doppler blueshift is used in astronomy to determine relative motion: The Andromeda Galaxy is moving toward our own Milky Way galaxy within the Local Group; thus, when observed from Earth, its light is undergoing a blueshift.