Why does marty snicker when she donates a day of algebra class for an outdoor excursion?
a) because she knows that everyone loves algebra and that everyone will be angry with her for losing a class day
b) because she is joking about how there is no question that being outdoors (or anything really) is better than algebra.
c) because she likes to make fun of mr. torres and his weird obsession with exotic and fragile plants from faraway places
d) because marty is clearly a sarcastic and unpleasant person to be around while at school, especially in mr. torres' class.