(short writing) Phototropism is a phenomenon observed in plants. Phototropism is best described as a plant’s response to light. Auxin is a hormone and signaling molecule found in plants that promotes cell elongation. It is observed that auxin concentrations are lower in the parts of the plant that are closest to light. Auxin concentrations are higher in the parts of a plant that are in the shade. Answer the following in the space provided.
Describe phototropism using what you know about signal transduction. Start with auxin as a signaling molecule.
Explain how altering the receptor would affect the signaling pathway.
Predict how a plant would respond to exposure to light on all sides of a growing stem.
Provide reasoning and justification for your prediction.

1) a) Auxin moves to the darker side of the plant, causing the cells there to grow larger than corresponding cells on the lighter side of the plant. This produces a curving of the plant stem tip toward the light, a plant movement known as phototropism. Auxin also plays a role in maintaining apical dominance.

c should be the answer

the right is separation by density .

take the blood which is a good example of a heterogeneous mixture.

blood is a vital liquid in our body, which transports oxygen from the air to our lungs so we can breathe. it is also used to eject wastes, such as carbon dioxide, to bring cells and molecules of the immune system to the tissues, and to spread hormones throughout the body. it corresponds to plasma, red blood cells, white blood cells, platelets and hemoglobins combined.

in medical tests centrifugal force is used to separate the different components of the blood.

in general, the centrifugation will allow to separate and analyze the different components of the blood, to know if the rate of white blood cells in the blood of a patient, for example, is normal, and therefore to know if his system immune is integrity.

under the action of centrifugal force, the solid components in the blood are drawn to the bottom of the tube in which the blood is contained. the centrifugal force then acts as an accelerated settling. it separates plasma from red blood cells and white blood cells.