If a cell has a cell membrane, it is ... A. eukaryotic.

B. prokaryotic.

C. can be either prokaryotic or eukaryotic.

D. none of these have a cell membrane.

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.

Explain how scientists use geologic time to determine the age of landforms.

Explain how sequences of amino acids in proteins can be used to reveal relationships among organisms.