The universe is often described as “clumpy” with dense groups of matter separated by empty space. a single clump made of billions of stars is known as a
a) galaxy.
b) nebula.
c) light year.
d) solar system.

A. Galaxy. is the correct answer. a galaxy is a colossal grouping of solar systems, and stars that slowly orbit each other, and other galaxies.

B. nebula. is incorrect. a nebula is a large collection of dust and small meteoroids.

C. light year. is not correct. light year- a large unit of distance, often used when measuring the distance between galaxies.

D. solar system. is incorrect. solar system- a group of planets and a star.

c) 50% there are four chromosomes. after crossing over, 2 of the four have been changed. that means any gamete has a 2 in 4 chance or 50% chance of receiving the mutated chromosome.