What else does the dog eating catfish feed on

true, i don't really know what you're asking but from the info you provided im guessing the answer is true.

not sure if this what   you'r looking for would be percent composition

he forelimbs below belong to four species that descended in a direct line from the ancestral mammal shown above. of the four descendants shown, which species most likely appeared earliest in evolutionary history?

not necessarily. higher fitness requires the organism to be reproductive successful. for example, an organism at age 10 with 15 offspring is much more fit than an organism at age 15 with only 5 offspring.