Ex Nihilo- Creation of life from nothing
World Parents- Creation resulting from the union of two natural forces
Emergence- Earth Emerging from water
Earth Diverse- The transfer of life from another world to earth
Well, let's go through the Alphabet and mention the letters that contain some closed space:
A, B, D, O, P, Q, R,
That's a total of 7 letters- so the correct answer is "seven"
In an alphabet of lower case letters there are many more, for example "e", "g"
He wants to convince readers that Buddhism is worth studying
The correct answer would be that all of the elements mentioned were part of St. Thomas Aquinas philosophical system. He considered himself an Aristotelian (followed Aristotle's teachings which in modern day are considered the development of Plato's teachings), an Empericist (it is the theory that all knowledge comes from sensory experiences) and a Neoplatonist ( believes mind over matter and that reality is subjective; depends on the highest principle). And since he was before anything a Christian theologian, then all the elements are part of his system.
It's because some people think that the the teachers they have might act like their second mother.