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) a control
b) an independent variable
c) a dependent variable
d) a constant

A control is that group in an experiment that does not receive any treatment and is used for comparison with the test result.

A) a control

Explanation:

In the experiment mentioned, the control is missing because the test group as mentioned are the plant set that receives the treatment that is the different concentration of nitrate and phosphate.

The effect of these nutrients on growth will be observed and evaluated. The time period of the experiment is one month which might exceed.

the correct answer is: d. the saltine and pretzel are made of flour, yeast, and baking soda, and salt. the pecan contains no flour but it does contain fats. the pecan is a nut that can be consumed as a healthy snack. first of all, pecans are a source of fat (monounsaturated fat), but they provide less fat than some other nuts. pecans are a rich source of dietary fiber, manganese magnesium, phosphorus, thiamin, vitamin e…

the sugar-phosphate backbone forms the structural framework of nucleic acids, including dna and rna. this backbone is composed of alternating sugar and phosphate groups, and defines directionality of the molecule.