Question Detail
Question
What material did Boysen-Jensen use to demonstrate that the growth stimulus could NOT pass through an impermeable barrier?
Correct Answer
Option D is the correct answer.
Detailed Explanation
Mica is a mineral that acts as an impermeable barrier. Boysen-Jensen showed that inserting mica on the dark side of the shoot prevented bending, whereas gelatin allowed it.
Hint
It's a thin, hard mineral sheet.