The physical expression of genes are phenotype. Phenotype is the expression of the gene by the appearnace of the organism. It is the characteristics of that trait.
Examples : When pigment is made in our eyes, height ( tall and short) , weight, blond hair is the phenotype for the blond hair genotype and skin colour( black, white ) is the phenotype trait.
Answer:
I think its c Scientists cannot determine how it changes.
d). It increases over time.
Facilitated diffusion is the diffusion of solutes through transport proteins in the plasma membrane. Facilitated diffusion is a type of passive transport. Even though facilitated diffusion involves transport proteins, it is still passive transport because the solute is moving down the concentration gradient.
