TASK DEFINITION: Given a scientific passage and an answer, generate a question for the given answer.
PROBLEM: Passage: The largest known virus, called mimivirus, is so large that scientists first mistook it for a bacterium. It was first discovered in amoeba, in 1992, and was identified as a virus in 2003. Scientists believe that mimivirus may cause certain types of pneumonia in humans. The core contains DNA, with the majority of the DNA in genes, and only 10% DNA of unknown function ("junk" DNA). Answer: mimivirus

SOLUTION: What is the largest known virus?

PROBLEM: Passage: Modern reptiles live in many different habitats. They can be found on every continent except Antarctica. Answer: reptiles

SOLUTION: Modern members of what broad animal group live in many different habitats and are found on every continent except antarctica?

PROBLEM: Passage: Figure 42.21 The spleen is similar to a lymph node but is much larger and filters blood instead of lymph. Blood enters the spleen through arteries and exits through veins. The spleen contains two types of tissue: red pulp and white pulp. Red pulp consists of cavities that store blood. Within the red pulp, damaged red blood cells are removed and replaced by new ones. White pulp is rich in lymphocytes that remove antigen-coated bacteria from the blood. (credit: modification of work by NCI). Answer: spleen

SOLUTION:
What organ is similar to a lymph node but is much larger and filters blood instead of lymph?