Select the correct answer. Which condition is a cause of impotency in men?
A.
undescended testicles that persist beyond puberty
B.
the inability of the penis to become erect
C.
a vasectomy, which is a surgical procedure to cut the vas deferens
D.
a low production of sperm in the testes
E.
the absence of the vas deferens in a male from birth

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?

Which of these has happened to your food by the time it reaches your small intestine? a. all the macromolecules have been broken down completely. b. lipids and starches have been partially broken down. c. starches and proteins have been partially broken down. d. proteins and lipids have been broken down into subunits.

Which statement describes compounds a. compounds are made of one type of atom. b. compounds cannot be represented by models. c. compounds are represented by chemical formulas. d. compounds cannot be broken down into simpler forms.