Explanation:
I'm guessing the answer is oxygen.
Endocasts of Homo erectus (left) and Homo sapiens (right) illustrate rapid increase in brain size. As early humans faced new environmental challenges and evolved bigger bodies, they evolved larger and more complex brains. Large, complex brains can process and store a lot of information.
If scientists believe that the newly discovered gene has two alleles A and a and that the alleles show incomplete dominance, the best way to prove this is to look for subjects who are homozygous with respect to the different alleles. The offsprings will all have the genotype of Aa and if indeed, the alleles show incomplete the dominance, the traits of the first generation will not manifest completely but a mixture of two will.
The answer is $10 because 160-150=10