Step 1: Understanding the Words.
- **Career** refers to a person's long-term professional journey or occupation.
- **Carrier** refers to a person or thing that carries something, such as a vehicle or an organism that transmits diseases.
Step 2: Creating Sentences.
- **Career:** He decided to pursue a career in medicine to help others.
- **Carrier:** The postal carrier delivered the letters every morning.
Final Answer:
\[
\boxed{\text{1. Career: He decided to pursue a career in medicine to help others.}}
\boxed{\text{2. Carrier: The postal carrier delivered the letters every morning.}}
\]