Meiosis.
Meiosis results in four cells of the original, each with a halved amount of chromosomes, you could say.
The answer is the second 1
The corpus callosum is a broad band of white matter. It connects both left and right cerebral hemispheres to allow communication. Also, it allows relaying of information to both hemispheres in order for the brain to function in a healthy way.
For the trait that is coded by a recessive allele to be expressed, the must be homology, which means that an offspring has to inherit that recessive allele from both its parents.
A dominant allele will dominate over the recessive allele, so for the trait coded by a dominant allele to be expressed, the offspring only needs to inherit the allele from one of its parents.
For example: "R" is brown eyes, "r" is blue eyes.
Now you get one R from each of your parents.
RR (homozygote) = brown eyes
Rr (heterozygote) = brown eyes
rr (homozygote) = blue eyes
