Answer;
C. A wall of stones and mortar
This would act as a model describing the cell membrane.
Explanation;
A cell membrane is made up of a phospholipid bilayer with embedded proteins.
A cell membrane hold the different components of the cell together and to protect it from the environment outside the cell. It acts as a boundary between the inside environment and the outside environment of a cell.
It regulates the materials that enters and exits the cell; through selective movement of substances in and out of the cell.
Every organism has a unique ecosystem within which it lives. This ecosystem is its natural habitat. This is where the basic needs of the organism to survive are met: food, water, shelter from the weather and place to breed its young. All organisms need to adapt to their habitat to be able to survive.
In a monohybrid cross with two heterozygous parents the result will be a genotypic ratio of 1:2:1 for homozygous dominant to heterozygous to homozygous recessive. The phenotypic ratio will be 3:1 dominant trait to recessive trait.
This is a diagram of a paramecium.
