Learning to sail is challenging and exhilarating it is also not the easiest thing to do Question 1 options: a) properly constructed sentence b) dangler c) lacks parallel parts d) run-on

d) run-on

Explanation:

It's missing a comma:

Learning to sail is challenging and exhilarating it is also not the easiest thing to do.

A run-on is a sentence in which two or more independent clauses (i.e., complete sentences) are joined without an appropriate punctuation or conjunction.

irony  

i hope this you and have a good day

~ashbelle