Aresearcher finds that white bread contains more preservatives and has a higher moisture content than wheat bread. she designs a test to determine whether the type of bread, white or wheat, affects the amount of mold growth. what must be done for the researcher to accurately measure the dependent variable?

The researcher will need to limit the dependent variable to white bread or wheat bread.

Explanation:

A dependent variable is one that is influenced by another variable, called an independent variable. In the case exposed in the question the dependent variable is fungal growth, this growth is influenced by the type of bread, since the fungal growth depends on the type of bread used by the researcher. The researcher should limit her assessment to one dependent variable and one independent variable at a time. Thus, we can conclude that what the researcher must do to accurately measure the dependent variable is to limit this variable to white bread or wheat bread.

The relationship between environment, variation and selection lay the foundation for natural selection and evolution.

Genetic variations are present among species due to number of reasons like recombination or crossing over during meiosis, mutations, random fertilization etc. These factors bring changes among the members of a species. Some of the species become better adapted to survive in a particular environment whereas some are not better adapted and become extinct over a period of time. The environment selects the organisms that are best adapted to survive and hence lead to variations.