Given a scientific passage and an answer, generate a question for the given answer.

Ex Input:
Passage: Protostomes and Deuterostomes Bilaterally symmetrical, triploblastic eucoelomates can be divided into two groups based on differences in their early embryonic development. Protostomes include phyla such as arthropods, mollusks, and annelids. Deuterostomes include. Answer: protostomes and deuterostomes

Ex Output:
What are the two groups that tripoblastic eucoelomates can be divided into based on early embryonic development differences?

Ex Input:
Passage: Most plant cells have a large central vacuole . It can make up as much as 90 percent of a plant cell's total volume. The central vacuole is like a large storage container. It may store substances such as water, enzymes, and salts. It may have other roles as well. For example, the central vacuole helps stems and leaves hold their shape. It may also contain pigments that give flowers their colors. Answer: vacuole

Ex Output:
Most plant cells have a large central what?

Ex Input:
Passage: Reflected waves have the same speed and frequency as the original waves before they were reflected. However, the direction of the reflected waves is different. When waves strike an obstacle head on, the reflected waves bounce straight back in the direction they came from. When waves strike an obstacle at any other angle, they bounce back at the same angle but in a different direction. This is illustrated in the Figure below . In this diagram, waves strike a wall at an angle, called the angle of incidence. The waves are reflected at the same angle, called the angle of reflection, but in a different direction. Notice that both angles are measured relative to a line that is perpendicular to the wall. Answer: angle of reflection

Ex Output:
When waves are reflected at the same angle, what is it called?