In this task, you are given a question and an answer, you would be asked to create the sentence based on the Question-Answer provided. It should be contained within the Question-Answer provided.

[EX Q]: Question: What occurs when an unstable nucleus emits a beta particle and energy? Answer: beta decay
[EX A]: Beta decay occurs when an unstable nucleus emits a beta particle and energy.

[EX Q]: Question: What is the only animal phyla that does not consist exclusively of invertebrates? Answer: chordates
[EX A]: Chordates is the only animal phyla that does not consist exclusively of invertebrates.

[EX Q]: Question: Unlike a crystalline solid, an amorphous solid is a solid that lacks a what? Answer: ordered internal structure
[EX A]:
Unlike a crystalline solid, an amorphous solid is a solid that lacks a ordered internal structure.