A student sets up an experiment and wants to see if different amounts of fertilizer affect the growth of basil. They place 4 separate plants in 4 same-sized pots. Each pot receives the same soil, the same amount of light, and the same amount of water. They add no fertilizer to Pot 1, 10g of fertilizer to Pot 2, 20g to Pot 3, and 50g to Pot 4. What are the fixed variables in this experiment?

POT 1
soil, light, water, type of plant
amount of fertilizer

pot size, soil, amount of light, type of plant, amount of water.

Explanation:

The fixed variables would be the pot size, soil, amount of light, type of plant, and amount of water.

There are three variables in a research experiment:

The fixed variables in an experiment are those variables whose values are kept constant throughout the course of the experiment. They are also referred to as controlled variables.

Independent variables are the actual variables being measured during an experiment.

The dependent variables are the variables being tested during an experiment.

The fixed variables are kept constant so as to be able to measure the effects that the independent variable will produce on the dependent variables during an experiment.

Hence, in this case, the fixed variables would be  the pot size, soil, amount of light, type of plant, and amount of water; the independent variable would be amount of fertilizer and the dependent variable would be a growth-determining factor.

the answer is d. chordata