The answer is A. The vascular system, filled with vascular tissue, are the crucial conduits through which water and nutrients flow through plants. Without them plants are limited to being a few inches (centimeters) tall. Leaves that get sunlight have nothing to do with a plants height.
You should always, and I mean always, use a <u>coverslip</u> on your slide. Without it, the contents on it would slip off and there'd be a big mess.
For extra security:
<em>Always make sure your stage clips are working! :)</em>
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I hope I helped! :)
