Since this is in the meditative section, rather than side-tracking the discussion with issues that do not pertain to meditation, it might be worthwhile to discuss how the material elements are used as a meditative practice.
5. The Reflection on the Material Elements
And further, monks, a monk reflects on this very body, however it be placed or disposed, by way of the material elements: "There are in this body the element of earth, the element of water, the element of fire, the element of wind."
Just as if, monks, a clever cow-butcher or his apprentice, having slaughtered a cow and divided it into portions, should be sitting at the junction of four high roads, in the same way, a monk reflects on this very body, as it is placed or disposed, by way of the material elements: "There are in this body the elements of earth, water, fire, and wind." -- MN 10.
The Reflection on the Modes of Materiality (Elements, Dhatu)
"And further, O bhikkhus, a bhikkhu reflects on just this body according as it is placed or disposed, by way of the modes of materiality, thinking thus: 'There are in this body the mode of solidity, the mode of cohesion, the mode of caloricity, and the mode of oscillation.'
"O bhikkhus, in whatever manner, a clever cow-butcher or a cow-butcher's apprentice, having slaughtered a cow and divided it by way of portions, should be sitting at the junction of a four-cross-road; in the same manner, a bhikkhu reflects on just this body, according as it is placed or disposed, by way of the modes of materiality, thinking thus: 'There are in this body the mode of solidity, the mode of cohesion, the mode of caloricity, and the mode of oscillation.' -- MN 10