Plants Do Not Have a Circulatory System Like That of Some
Plants do not have a circulatory system like that of some animals. If a water molecule in a plant did "circulate" (that is, go from one point in a plant to another and back in the same day), it would require the activity of ________.
A) only the xylem
B) only the phloem
C) only the endodermis
D) both the xylem and the phloem
Some botanists argue that the entire plant should be considered as a single unit rather than a composite of many individual cells. Which of the following cellular structures best supports this view?
A) cell wall
B) cell membrane
Plasmodesmata can change in number, and when dilated can provide a passageway for ________.
The symplastic route can transport ________.
A) sugars, mRNA, and mitochondria
B) mRNA, mitochondria, and proteins
C) mitochondria, mRNA, and viruses
D) viruses, sugars, and mRNA