Aresearcher is interested in the effects of nitrate and phosphate on plant growth and sets up an experiment in which groups of five plants are given 1, 2, and 3 grams of nitrate and 1, 2, and 3 grams of phosphate in all combinations over a period of one month. the researcher measures plant height and weight at the end of the experiment. what is missing in this experimental design?

a control      

Explanation:

A controlled experiment is the scientific study or test done which can be directly manipulated by the experimenter. This is done to test a single variable one at a time. The variable which is tested is independent variable and is then adjusted to see the effects on the system that is studied.

In the context, a researcher sets up an experiment and takes readings of the height and weight of the variable. But the experimenter did not included a controlled experiment.

corrupt also means cruel

i disagree that there is little difference between adult female development and adult male development. sociological studies comparing female and male pathways to adulthood, revelead that there are sustancial differences between them. particularly, female and male differ from timing of marriage, when they began to live with children and the likelihood of combining wife/husband and parent roles.