5. Some medical researchers assert that rays of intense radiation originating from solar flares and estimated at three to four times greater than the frequency of visible light damage human skin cells and prolonged exposure can lead to serious burns.
a. at three to four times greater than the frequency of visible light damage
b. as being three to four times greater than the frequency of visible light damages
c. that it is three to four times greater than the frequency of visible light damages
d. to be three to four times greater than the frequency of visible light damage
e. as three to four times greater than the frequency of visible light damage
OA: d
a. at three to four times greater than the frequency of visible light damage
b. as being three to four times greater than the frequency of visible light damages
c. that it is three to four times greater than the frequency of visible light damages
d. to be three to four times greater than the frequency of visible light damage
e. as three to four times greater than the frequency of visible light damage
OA: d
