Look at the image below. The posterior end of two roundworms (Ascaris lumbricoides) is shown below. What structure is indicated by the red arrow?  

I conduct a study on the effect of a low carb diet on weight loss among people with a mobility issue. I use their weight that was recorded in the OT hospital clinic today and then measure their weight using my bathroom scale form home 4 weeks later. This could cause a threat to internal validity known as:

To what subphylum do the crabs, crayfish, shrimp, isopods, copepods, lobsters, etc. belong?

To what class do the centipedes belong?

Which of the following is CORRECT concerning echinoderms?

A hospital administrator is examining gender differences in annual salary among health care executives. He hypothesizes that the average salary for men is higher than that of women. What type of hypothesis is this?

What is the most common intestinal parasite in the US?

Which of the following statements concerning roundworms is ACCURATE?

In the life cycle of Dirofilaria immitis, what system is affected by the infection?

Which of these is an advantage of metamerism?