Which condition is essential for natural selection to result in a new species?

Will someone me with this.. specialized cells which perform a particular function form: tissues organs or organism

In a cross between individuals of a species of tropical fish, all of the male offspring have long tail fins, and none of the females possess the trait. mating two of the f1 fish fails to produce females with the trait. explain the inheritance pattern of the trait.

Recombinant dna (rdna) creates offspring which are genetically identical to the parent is the process of breeding only organisms with desirable traits involves the removal of the nucleus of a cell combines genes from organisms of different species in a lab