A euglena is a photosynthetic microorganism that moves by making whip-like motions with its long flagellum.

Picture: http://tinypic.com/r/20iuwpg/6

Which of these is a response to an external stimulus?
A) Expulsion of waste
B) Production of glucose
C) Size of the chloroplast
D) Movement toward light

I believe it to be D, not entirely sure.

Question

A euglena is a photosynthetic microorganism that moves by making whip-like motions with its long flagellum.

Picture: http://tinypic.com/r/20iuwpg/6

Which of these is a response to an external stimulus?
A) Expulsion of waste
B) Production of glucose
C) Size of the chloroplast
D) Movement toward light

I believe it to be D, not entirely sure.

anonymous · Answer

I think you're right - light would certainly be an external stimulus.