Humans aren't the only ones getting a buzz from coffee.Caffeine can improve memory among honeybees and lead to better pollination .According to a recent study published in the journal Science. The study was conducted by a team of researchers at Newcastle University in the United Kingdom.They found that the nectar of some flowers,such as those from grapefruit and lemon plants,as well as certain coffee flowers,contains low doses of caffeine.To get bees to feed on these flowers,the team trained the insects to associate food with the smell of the flowers.They also trained another group of bees to feed on nectar from flowers that were sweetened with a sugar, but did not contain caffeine.After 24 hours,the bees trained on caffeinated flowers returned to these plants three times as often as those trained on the sweetened flowers returned to the uncaffeinated plants. Professor Geraldine Wright led the researchers."Remembering floral traits is difficult for bees to perform at a fast pace as they fly from flower to flower and we found that    caffeine helps the bee remember where the flowers are,"Wright said in a statement. Improved memory led to the better pollination.That's because once bees sip the caffeine  nectar, they continue to look for more coffee plants to pollinate.This also suggests that caffeine  plays a role in improving the bees'ability to search for food. Researchers found that caffeine's effect on the bee brain is similar to its effect on mammals."The change is similar to that produced by caffeine in neurons associated with learning and memory in the rat brain,"Wright said. Bee populations have declining since 2007.The dramatic drop in the insects'numbers has  serious effects for ecosystems and the farming industry.Bees are needed in the reproduction of  crops and spreading wild flower species.Understanding what keeps bees buzzing could help to make sure that the insects are able to remember and pollinate their favorite flowers. Which of the following relationship is correct according to the passage?
improved memory--caffeine nectar--better pollination caffeine nectar--improved memory--better pollination improved memory--better pollination--caffeine nectar caffeine nectar--better pollination--improved memory