TASK DEFINITION: Given a scientific passage and an answer, generate a question for the given answer.
PROBLEM: Passage: The first period of the Paleozoic Era was the Cambrian. By the beginning of the Paleozoic, organisms evolved shells. Shells could hold their soft tissues together. Shells could protect them from predators and from drying out. Some organisms evolved external skeletons. These are called exoskeletons . Organisms with hard parts also make good fossils. Fossils from the Cambrian are much more abundant than fossils from the Precambrian. Answer: cambrian

SOLUTION: The first period of the paleozoic era was called what?

PROBLEM: Passage: Some molecules, such as proteins, are too large to pass through the plasma membrane, regardless of their concentration inside and outside the cell. Very large molecules cross the plasma membrane with a different sort of help, called vesicle transport . Vesicle transport requires energy, so it is also a form of active transport. There are two types of vesicle transport: endocytosis and exocytosis. Both types are shown in Figure below and described below. Answer: active transport

SOLUTION: What type of transport is vesicle transport considered to be?

PROBLEM: Passage: We have a main sequence star nearby. Our Sun is on the main sequence, classified as a yellow dwarf. Our Sun has been a main sequence star for about 5 billion years. As a medium-sized star, it will continue to shine for about 5 billion more years. Most stars are on the main sequence. Answer: yellow dwarf

SOLUTION:
Our sun is on the main sequence, like most stars, and it is classified by what colorful name?