Which of the Following Descriptions Constitutes a Controlled Experiment

question 22

Multiple Choice

Which of the following descriptions constitutes a controlled experiment?

• A)using a microscope to observe organisms present in a sample of pond water and recording the number of each type of organism observed
• B)setting up a bird feeder and compiling a list of all of the bird species seen at the feeder over a period of several weeks
• C)growing one set of 10 seedlings under white light and one set of the same type of seedlings under red light and measuring their growth over a period of two weeks
• D)growing one set of 10 seedlings under white light at 30°C and one set of a different type of seedlings under red light at 25°C and measuring their growth over a period of two weeks

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Definitions:

Hox Genes

Hox genes are a group of related genes that control the body plan of an embryo along the head-tail axis by specifying regions of development in early embryonic segments.

Animal Evolution

The gradual development of diverse species of animals over geological time from common ancestors through changes in traits and genetics.

Blastopore

The initial opening that develops during early embryonic development in animals, leading to the formation of the digestive tract.

Deuterostomes

A grouping of animals characterized by their embryonic development; during the formation of the mouth and anus, the anus forms before the mouth.