Question

instructions: for the following experiments, identify and describe the (iv) independent variable, (dv) dependent variable, (cg) control group, and (con) the constant.

1. different rose bushes are grown in a greenhouse for two months. the number of flowers on each bush is counted at the end of an experiment.
2. you water three sunflower plants with salt water. each plant receives a different concentration of salt solutions. a fourth plant receives regular water. after a two - week period, the height is measured.
3. three wax palm trees are kept at different humidity levels inside of a greenhouse for 12 weeks. one tree is left outside in normal conditions. height of the tree is measured once a week.
4. one tank of goldfish is fed the normal amount of food once a day, a second tank is fed twice a day, and a third tank four times a day during a six - week study. the fishs body fat is recorded daily.
5. strawberry plant clones are given different amounts of water for a 3 - week period. first strawberry plant receives 400 millilitres (ml) a day. the second strawberry plant receives 200ml a day. the third strawberry plant receives 100ml a day. the fourth strawberry plant does not receive any extra water; this plant only receives natural ways of receiving water. the height of the strawberry plants is recorded daily.

Explanation:

1. In the rose - bush experiment, the number of flowers depends on the type of bush, so the type of rose bush is the independent variable (IV) and the number of flowers is the dependent variable (DV). The control group could be a standard type of rose bush, and constants might include the greenhouse environment, time period.
2. For sunflower plants, the concentration of salt in the water is what is being changed (IV), and the height of the plant is the measured outcome (DV). The control group could be plants receiving regular water, and constants include the type of plant, time of the experiment.
3. With wax palm trees, humidity level inside the greenhouse is the IV as it is manipulated, and the height of the tree is the DV. The control is the tree outside in normal conditions, and constants are the type of tree, measurement time - interval.
4. In the goldfish experiment, the feeding frequency is the IV, and the fish's body fat is the DV. The control group is the normally - fed fish, and constants are the type of fish, tank environment, study duration.
5. For strawberry plants, the amount of water is the IV, and the height of the plant is the DV. The control is the plant with natural water supply, and constants are the type of plant, time of the experiment.

Answer:

1. IV: Type of rose bush; DV: Number of flowers on each bush; Con: A standard type of rose bush; CG: A normal type of rose bush grown in the greenhouse; Constants: Greenhouse environment, two - month time period.
2. IV: Concentration of salt in water; DV: Height of the plant; Con: Plants receiving regular water; CG: A plant receiving regular water; Constants: Type of sunflower plant, two - week time period.
3. IV: Humidity level inside the greenhouse; DV: Height of the tree; Con: Tree outside in normal conditions; CG: A tree outside in normal conditions; Constants: Type of wax palm tree, one - week measurement interval, 12 - week experiment duration.
4. IV: Feeding frequency; DV: Fish's body fat; Con: Normally - fed fish; CG: A normally - fed fish; Constants: Type of goldfish, tank environment, six - week study duration.
5. IV: Amount of water; DV: Height of the plant; Con: Plant with natural water supply; CG: A plant with natural water supply; Constants: Type of strawberry plant, three - week time period.