Match the following terms to their definitions. a. empirical evidenceb. independent variable c. dependent variable d. controle. hypothesis1. the variable that changes in response to experimentation 2. data or facts that can be observed 3. the quantity in an experiment that remains unchanged 4. the experimental factor that is changed by the scientist 5. a proposed explanation for a scientific problem

1c; 2a; 3d; 4b; 5e

Explanation:

Empirical evidence: data or facts that can be observed

Independent variable: the experimental factor that is changed by the scientist

Dependent variable: the variable that changes in response to experimentation

Control: the quantity in an experiment that remains unchanged

Hypothesis: a proposed explanation for a scientific problem

A scientist conducts experiments to test an hypothesis. During the experiment, a single independent variable is changed under controlled conditions and the effects of those changes are observed and measured on the dependent variable. All other possible variables in a given experiment need to be maintained constant and are called controls. The obtained results are the empirical evidence.

For example, if you wanted to test whether watering frequency affects plant growth, you could have many plants of the same species and water each of them with different frequency (independent variable). You could then consider the length of the stem of each plant as a measure for growth (dependent variable). All other variables (nutrient content, temperature, light exposure, etc.) need to be constant (control). If you observed that the plants that were watered more frequently had as a result longer stems (empirical evidence) you could hypothesize an explanation (for example, higher water availability increases nutrient uptake by plants, allowing them to grow more) and then conduct further experiments to test it.

both male and female gametes are produced by meiosis of the germ cells. therefore, both male and female gametes are haploid. one male and one female gamete unite during the fertilization to form the diploid zygote. in seed bearing plants, pollen grain is the male gametophyte, which produces sperm cells.