Confident middle-aged male teacher or professor standing in front of a chalkboard with books folded arms.

Related tags:

• lesson
• tutor
• teaching
• academic
• educational
• school teacher
• study
• school
• learning
• teacher teaching
• high school
• professor
• knowledge
• university
• clever
• teacher
• male teacher
• chalkboard
• book
• nerd
• face portrait
• face
• male
• portrait
• science
• scientist
• 20+