A variation of this reaction has also been performed by undergraduates, where benzaldehyde (PhCHO) is used instead of 9-anthraldehyde. How many stereoisomers would be possible for the product of this Wittig reaction? (your answer should be an integer number)

the correct answer is:

a. formation of precipitation

sup bro, im dumb, but this is what i found xd

"the ozone layer acts as a filter for the shorter wavelength and highly hazardous ultraviolet radiation (uvr) from the sun, protecting life on earth from its potentially harmful effects. when the sky is clear, there is an inverse relationship between stratospheric ozone and solar uvr measured at the earth's surface"