Which examples describe how a plant might meet the challenge of getting and using energy?

a.
in a forest, trees grow tall and branches grow long to get enough sunlight.

b.
leaves on trees turn green in the spring due to increased sunlight, which allows for photosynthesis.

c.
potato plants store food in underground potatoes for use when necessary..

d.
a cactus has spines to ward off predators.

The answer is A.

In a forest, especially a rainforest, trees must grow rapidly to reach the sun at the canopy. In order to be competitive, they grow tall without as wide as trees in moderate climates.

Most trees  in these  tropical regions have straight trunks with no branches or leaves until they reach the canopy layer. Below this layer there is very little sunlight and trees have adapted to growing branches and leaves where sunlight can be obtained.

Most trees in the rainforest grow rapidly to escape the darkness of the forest floor to reach the needed sunlight of the canopy.  When a gap in the canopy appears, for example due to a fallen tree, the small trees are capable of a growth surge  in order to take advantage  of the opportunity for sunlight. 

c

explanation:

the right choice would be a. culture within the city-state. c. loyalty to the police. d separation by land and sea.