Answer:
You say there is one twin. Twins, when referred to as a set, require an s, just like most other groups of objects. There are the twins.
We the People of the United States, in Order to form a more perfect Union, establish Justice, insure domestic Tranquility, provide for the common defence, promote the general Welfare, and secure the Blessings of Liberty to ourselves and our Posterity, do ordain and establish this Constitution for the United States of America.
<5 and <6 are not linear true pair 5 could be a linear pair
D. the rest are the government branches :)
