Answer:
CO2 is a nonpolar molecule that can diffuse through the plasma membrane. As long as it diffuses away so that the concentration remains low outside the cell, it will continue to exit the cell in this way.
Explanation:
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.
Phospholipids make up parts of the cell membrane and their in a whole different setting .
The correct answer is b, antigens
