"this discovery" as stated in the text is actually referring to "laughter may have healing properties".
From the passage, we discover that it was stated that the doctors reveal that laughter may have healing properties.
Also, the last line of the text revealed that "the discovery" is having a phenomenal influence on health care. It is only laughter that can bring something phenomenal among the other options given.
Something phenomenal is referring to something remarkable. Therefore, laughter is what can make bring a phenomenal influence on health care.
Gawain stepped in to accept the challenged. He chopped off the Knight’s head but it
magically reattached itself back to its body.
A year later he travels to the Green Knight’s lair where it is his turn
to accept a blow from him. When the
Knight strikes, Gawain only to evade the blow.
He goes home afterwards.
The reason is because the sky overcast system is to go into the sky and try to figure out the wheater which would be a dependent clause in this situation please let my know if im wrong :) hope it helps
While the main idea is usually in the first sentence, the next most common placement is in the last sentence of a paragraph. The author gives supporting information first and then makes the point in the last sentence.