One in twenty people have an extra rib.
Twenty is an integer. Not sure what you mean with "in humans".
The twenty-three chromosomes in humans is called a haploid number. It refers to the number of chromosomes in a gamete of an organism.
28"21" but to be extra smart the answer is "The seventh triangular number is twenty one."
Down syndrome occurs when an individual receives an extra 21st chromosome.
Humans have twenty deciduous teeth.
yes
Yes, extra nipples are very common. Depending on the place where the study was done, the incidence can range from one in two hundred to one in twenty people.
one hundred twenty-eight
One in particular was mastering EVA (Extra Vehicular Activity). He proved that humans can work in space.
121 is one twenty-one
humans have 26 of these rods, a crossword with 10 spaces, 2nd H 10th is e
There is not a factual answer to give for this question. Some people believe that it exists and some people do not believe it exists.