The cells in the stem of a plant often have thicker cell walls than the other parts of the plant in order to a. allow more light to penetrate through the stem. b. secrete water and oxygen through the stem. c increase gas exchange in the stem. d provide support and strength to the stem.

What is hydroelectric power produced by?

Organisms are classified, or grouped into categories, based on similarities in their characteristics and/or evolutionary relationships. the study of how organisms are classified is known as

(drag each tile to the correct location.) categorize each term as something that is typical of a scientific theory, a scientific hypothesis, or both. - a tentative statement used to guide scientific investigations. - makes predictions about future events. - can be tested by many independent researchers. - based on observations of natural phenomena. - a well-established, highly reliable explanation.