Consider the following main functions of plants : A. To produce and store food…

A flowering plant's vegetative body has three organs, each with a distinct principal role: the root absorbs water and minerals from the soil; the leaf is the plant's principal food-manufacturing organ, carrying out most of the plant's photosynthesis with its chlorophyll (a green stem can photosynthesise too, but this is not its principal role); and the stem's principal roles are mechanical and conductive -- it holds the plant's aerial parts (leaves, flowers, fruits) in a supported, upright position, and its vascular tissue conducts the water and minerals absorbed by the root up to the rest of the plant.

Applying this to the three given statements: Statement B (giving strength and support) names one of the stem's principal roles directly. Statement C (transporting water and minerals from roots to other parts) names the stem's other principal role directly. Statement A bundles two distinct things -- producing food and storing food. Producing food is carried out mainly through photosynthesis in chlorophyll-bearing tissue, principally the leaf; storing food happens in particular organs of particular plants (a carrot's root, a potato's modified stem, a fruit, or a seed). Neither producing food nor storing food is a general, principal function of an ordinary stem in the way that support and conduction are. So among the three statements, B and C name the stem's principal functions, while A does not.

• Only B names the support role; carrying water and minerals from the root to the rest of the plant, through the stem's vascular tissue, is the stem's other principal function, distinct from support.

• Only A and B names support along with producing and storing food; producing food occurs mainly through photosynthesis in chlorophyll-bearing tissue, and storing food happens in particular organs of particular plants -- neither is a general, principal function of an ordinary stem, while conduction of water and minerals is a principal stem function not named here.

• A, B and C names support and conduction along with producing and storing food; producing and storing food are not general, principal functions of an ordinary stem, for the reasons above.

Hence, the main functions of the stem, among the given statements, are captured only by B and C.