One is the long-distance transport of bees for pollination and the spread of bee diseases from one area to another.

VOA: special.2011.05.24

Notice that these transport costs go up in the distance you have to travel and they go up pretty fast.

注意这些交通成本,随着距离而增长并且增长得很快

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So Y is the distance they have to travel and TY2 is their transport cost.

所以Y是他们要走的距离,而TY2是交通成本

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