Because of the increase in hydrostatic pressure
Its called the convolution
also known as the Gyrification of the brain, it increase the brain surface area , allowing more neuron capacitiy to process information
its located in cerebral cortex and become a place where our brains store our memories.
You need two recessive alleles (xx). If even one dominant allele is present, the dominant trait will show (Xx or XX will both result in the dominant trait showing). That’s why they’re called dominant traits, because they overpower the recessive traits. In order for a recessive trait to show you must have two recessive alleles.
A flatworm does not have a body cavity.