Given a scientific passage and an answer, generate a question for the given answer.
One example: Passage: A frameshift mutation is a deletion or insertion of one or more nucleotides that changes the reading frame of the base sequence. Deletions remove nucleotides, and insertions add nucleotides. Consider the following sequence of bases in RNA:. Answer: nucleotides.
Solution is here: A frameshift mutation is a deletion or insertion of one or more of what that changes the reading frame of the base sequence?
Explanation: The science passage defines frame mutation and the main compoment here is nucleotides. Hence the generated question is apt.

Now, solve this: Passage: Many prokaryotes have an extra layer, called a capsule, outside the cell wall. The capsule protects the cell from chemicals and drying out. It also allows the cell to stick to surfaces and to other cells. Because of this, many prokaryotes can form biofilms, like the one shown in Figure below . A biofilm is a colony of prokaryotes that is stuck to a surface such as a rock or a host's tissues. The sticky plaque that collects on your teeth between brushings is a biofilm. It consists of millions of bacteria. Answer: prokaryotes
Solution:
A biofilm is a colony of what that is stuck to a surface such as a rock or a host's tissues?