Energy holds them together.
Answer:
<u>A</u> One of the key elements in creating a green economy is the construction of <u>green buildings</u>.
Explanation:
Any economy relies on businesses and buildings, so a green economy is going to need green buildings to support a green economy as well.
I believe it is A because Living things respond to changes, each and every living organism is made up of cell and adapting to changes is same as responding to changes.So, only one left is A.