Every compound can be represented by a chemical formula. A chemical formula is the set of symbols showing the elements that make up a compound and their proportions. Water’s chemical formula is H_2 2 O. That means a molecule of water contains two atoms of hydrogen and one atom of oxygen chemically bonded. A molecule is a group of two or more atoms bonded together. Molecules can range in size from two to thousands of atoms. A molecule of a compound is the smallest unit of that compound. Every molecule of water has all the physical and chemical properties of water. That’s because every molecule of water is made of the same elements in the same proportions: two hydrogen atoms and one oxygen! Which of the following is a true statement? A
Every molecule of the same compound will have different properties.

B
Every molecule of a compound has the same proportion of elements.

C
Molecules can be physically separated into smaller units of a compound.

D
Molecules cannot be represented by chemical formulae.

What is unique about the members of the group of fungi to which penicillium notatum belongs? they are not important for medicine. they are not made up of hyphae. they are used in fermentation. they lost the reproductive phase.

Which of the following occurs most often in a population when genetic variation and overproduction are present? some organisms have a lower reproductive success than others. some organisms have a higher reproductive success than others. some organisms have no reproductive success. some organisms do not have genetic variation.

The collared lizard is a species found in the desert southwest. male collared lizards show considerable color variation, ranging from brightly colored to a very dull pattern. your goal is to determine the function, if any, of male color patterns in collared lizards, using the scientific method. your tentative explanation is that male color plays a role in attracting females for mating purposes. you predict that females will preferentially choose brightly colored males over dull-colored ones. to test this prediction, you observed the interactions of female collared lizards with their male counterparts. you selected males that were the same age and size, and that differed only in their coloration pattern. you placed equal numbers of the two types of male lizards, bright and dull, in aquariums, along with one female lizard per aquarium. out of 350 aquariums observed, the female chose to mate with the brightly colored male 277 times, and the dull-colored male 70 times. in 3 instances, the females did not mate with either type. create a bar graph of your data, plotting the type of male (dull or brightly colored) on the x-axis. on the y-axis, plot the frequency with which each type of male was chosen by females. using this graph, answer the following question(s). is it reasonable to conclude (i.e., is it supported by the data) that female collared lizards prefer more brightly colored male lizards over dull-colored males?