Final answer:
The correct answer to the student's question about amniocentesis and DNA is option b: all living things contain DNA, as it is the genetic material found in all living organisms.
Step-by-step explanation:
Amniocentesis is a procedure where fluid is removed from the uterus for testing. This fluid contains fetal cells that can be analyzed for genetic health indicators and abnormalities. In response to the student's question, the correct answer would be: b. all living things contain DNA. This is because DNA is the hereditary material found in all living organisms and plays a crucial role in passing genetic information from one generation to the next. Unlike the other options provided, which are either incorrect or inaccurate, all living things do indeed contain DNA. It is noteworthy that DNA consists of four types of bases (not three), which combine in various ways to form the genetic instructions that are unique to each individual (excluding identical twins).