Explain
Definition
Give reasons for how or why something happens.
Explanation
An explanation connects a cause to an effect and includes the reasoning. Phrases such as "because", "so" and "which means" are typical.
Example
Explain why ice floats on water.
In an exam
Command-word meanings can vary between subjects, exam boards and mark schemes, so check your own board's guidance. See Exam Command Words: What Each Instruction Asks For.
Common confusion
Explain is more than describe. A list of facts without reasons is not an explanation.