Read the passage and answer the following questions:
The principle of selection solved the riddle as to how what was purposive could conceivably be brought about without the intervention of a directing power, the riddle which animate nature presents to our intelligence at every turn, and in the face of which the mind of a Kant could find no way out, for he regarded a solution of it as not to be hoped for.
For, even if we were to assume an evolutionary force that is continually transforming the most primitive and the simplest forms of life into ever higher forms, and the homogeneity of primitive times into the infinite variety of the present, we should still be unable to infer from this alone how each of the numberless forms adapted to particular conditions of life should have appeared precisely at the right moment in the history of the Earth to which their adaptations were appropriate, and precisely at the proper place in which all the conditions of life to which they were adapted occurred: the humming-birds at the same time as the flowers; the trichina at the same time as the pig; the bark-coloured moth at the same time as the oak, and the wasp-like moth at the same time as the wasp which protects it. Without processes of selection, we should be obliged to assume a "pre-established harmony" after the famous Welshman model, by means of which the clock of the evolution of organisms is so regulated as to strike in exact synchronism with that of the history of the Earth!
All forms of life are strictly adapted to the conditions of their life and can persist under these conditions alone. There must, therefore, be an intrinsic connection between the conditions and the structural adaptations of the organism, and, since the conditions of life cannot be determined by the animal itself, the adaptations must be called forth by the conditions. The selection theory teaches us how this is conceivable. Since it enables us to understand that there is a continual production of what is non-purposive as well as of what is purposive, but the purposive alone survives, while the non-purposive perishes in the very act of arising.
This is the old wisdom taught long ago by Empedocles.