Your answer would be A because none of the others make sense, Hope that helps!
If the epimers differ in con²gura±on around one<span> carbon or more than one carbon</span>
Diffusion is the movement of particles from a high concentration area to a low concentration area.
Things that can go through a membrane are ions (charged), small polar molecules. Big molecules can't go through the membrane due to its large size and disrupting the membrane.
Passive transport is the movement of substances acrpss the cell membrane w/o the use of energy. Active transport needs energy to move substances across a cell membrane.
Evolution Due to environmental factors, It may not look it, but, needles are leaves, they collect solar radiation to produce glucose through the process of photosynthesis, however, needles are, some would say, evolutionary superior to leaves. Needles themselves hold in more water due to their dense wax coating, they are very difficult for insects and other organisms to eat, one because of their structure, and two because of their acidity, they can catch sunlight all year long due to their winter resilience( they don't fall, during the winter), and they have less surface area for wind to catch, which leaves them better protected from wind than most deciduous trees, however the surface area can also pose a larger problem for less surface area means less sunlight interception, therefore more are needed to compete against regular leaves. But.. I Digress... Plant needles are 'PROBABLY' initially the result of evolution of narrow leaves due to climate or environmental factors.
Sry its so long got carried away! Hope this helps xD