Abutterfly can mate with another butterfly to produce fertile offspring only if the two butterflies belong to the same
a) family.
b) genus.
c) order.
d) species.

Which of the following is the most likely result of converting forestland to urban development? a. the amount of land available for lumber production decreases. b. fewer trees are needed because cities are made mainly of concrete. c. people discover more efficient ways to grow trees. d. the price of lumber goes down.

Sydney drew a flow chart to illustrate the nitrogen cycle. which labels best complete the flow chart? x: producers undergo photosynthesis. y: nitrogen compounds are released into the air. x: nitrogen compounds are released into the air. y: producers undergo photosynthesis. x: free nitrogen is in the atmosphere. y: producers absorb nitrogen compounds through their roots. x: producers absorb nitrogen compounds through their roots. y: free nitrogen is in the atmosphere.

Did the vinegar diffuse all the way to the center of any of the cubes? if so, which ones? what does this tell you about surface area-to-volume ratio and the diffusion rate?