In humans, having two eyebrows is a completely dominant trait. The recessive trait is
expressed as having a single connected eyebrow. If a two parents who are heterozygous for
the eyebrow trait had an offspring, what is the probability that their child would express the
dominant phenotype?

The baby would most likely carry that trait  

Explanation

The chances of the child to be similar in a way could happen or not. The probability rate wouldn't be close to either parent even thought most of the time the child takes after the mother.

in 1859, charles darwin set out his theory of evolution by natural selection as an explanation for adaptation and speciation. he defined natural selection as the "principle by which each slight variation [of a trait], if useful, is preserved".