Combine the two sentences using appropriate punctuation and conjunctions.
She was exhausted. She had been traveling for 10 hours.
She was exhausted because she had been traveling for 10 hours.
Complete the following task based on the instruction and optional input provided.### Instruction:
Combine the two sentences using appropriate punctuation and conjunctions.

### Input:
She was exhausted. She had been traveling for 10 hours.

### Output:
She was exhausted because she had been traveling for 10 hours.