Apple

Apples were a common fruit found on Earth.

The Doctor once claimed that he hid up a tree and dropped apples on Isaac Newton's head. (DW: The Pirate Planet)

Whilst visiting the Worldsphere, the Doctor met a parachute that designed apple trees in its spare time. (NA: The Also People)

Following his ninth regeneration, the Doctor found an apple in a dressing gown that had been provided for him by Jackie Tyler. (DW: The Christmas Invasion)

Following his tenth regeneration, the Doctor thought he wanted an apple but didn't like it. Amelia Pond disliked apples when she was young, until her mother began carving happy faces into them. She gave an apple with a carved happy face on it to the Doctor, who promised to keep it for later. After travelling forward 12 years, the Doctor proved his identity to now-grown Amy Pond by showing her the same apple, still fresh. (DW: The Eleventh Hour)