I always though resin was there to attract more pollen and protect from UV light. If you let a plant seed, resin production goes down slightly(prolly form energies needed to produce seeds, or the fact that it has propogated). Also when you expose an indoor cannibis plant to UV light it produces more resin, somewhat of a "sunscreen."
Deer and animals are more likely to eat the seeds with the fruit, then leave a seed deposit elsewhere than to have the seeds sticking to fur. Most seeds that are eaten are attached inside(raspberries) or outside(strawberries) to a delicious fruit(like mari
) Most plants that travel by sticking have little prickers or bistles that are like fishhooks or barbs that are on its outer casing or shell that snag onto anything, Just like when you take your dog hunting and it when you get home you gotta brush your dog to keep it from matting up(and then dress some birds or rabbits for dinner.
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