The diagram is a model of one way that materials move across the cell membrane. Oxygen molecules are represented by two red circles. Carbon dioxide molecules are represented by a gray circle with two red circles attached. The left-hand side of the diagram shows the beginning concentrations of the two types of molecules. The right-hand side shows how the molecules have moved over time. sss Which sentence best explains the movement of the oxygen molecules over time?

This is one form of rna that transports a specific amino acid to a ribosome during protein synthesis.

Asolution of an enzyme and a substrate was placed in a water bath and the temperature of the reaction was raised gradually. the graph shown was plotted at the end of the experiment. what can be concluded from the graph? a) temperature has no effect on the activity of the enzyme. b) the effect of temperature on the enzyme is unpredictable. c) the enzyme shows increased activity up to a certain temperature. d) the activity of the enzyme is inversely proportional to the temperature.

Which of the following would involve looking at different structures of organisms and comparing how similar they are? a. vestigial structuresb. radiometric datingc. homologous structures