Astudent wants to answer the question “does adding calcium powder to soil make pea plants grow faster? ”? she adds calcium powder to the soil of 12 plants and does not add it to the soil of a second group of 12 plants. she measures the growth of all of the plants in each group for a month. which statement best summarizes the factors that need to be controlled in this experiment? a. all plants should be the same age and health and be given equal amounts of water and sunlight. b. all plants should be placed in separate, equal-sized pots on the same table, where they receive the same amount of sunlight. c. all plants should be watered in the morning at the same time each day, and given the same amount of soil and sunlight. d. all plants should be the same health and be given equal amounts of water, calcium, and sunlight.

The correct answer would be a. all plants should be the same age and health and be given equal amounts of water and sunlight.

Controlled variables are the variables, the value of which are kept constant throughout the experiment.

It helps in determining the effects of the independent variable (amount of calcium) accurately on the dependent variable (growth of a plant).

Controlled variables include temperature, disease-free conditions, amount and quality of food, water, and other living conditions of all the organisms under the experiment.

In this experiment, controlled variables include health, age, and amount of water and sunlight (as photosynthesis helps in plants growth).

mendel's first law states that during the formation of reproductive cells , pairs of hereditary factors for a specific trait separate so that offspring receive one factor from each parent.

explanation:

linnaeus is the father of taxonomy, which is the system of classifying and naming organisms. one of his contributions was the development of a hierarchical system of classification of nature. today, this system includes eight taxa: domain, kingdom, phylum, class, order, family, genus, and species.