Question

xylem and phloem are to plants as which of these are to humans? skin and bone, arteries and veins, arms and legs, brains and nerves

Explanation:

Xylem and phloem are plant - transport tissues. Xylem transports water and minerals, phloem transports nutrients. Arteries and veins in humans transport blood (oxygen, nutrients, etc.). They are analogous in their transport functions.

Answer:

arteries and veins