Hybrid vigor, in the parlance of a fish biologist, means that crossbred species are generally tougher, more adaptable, and more aggressive than either parent. What's true for fish is also true for trucks-in this case, the 2001 Ford Explorer Sport Trac. Here's a unique vehicle, built on the popular Explorer platform, which combines the best attributes of pickups and sport utilities. Need seating for four (and four doors)? Done. Need an open bed for muddy gear and deer? Done. All this and four-wheel-drive (MSRP: $25,180) as well. For information, see your Ford dealer, or go to www.ford.com.