How to Explain Bad Grades

I received a B in lacrosse in my freshmen year. This was COVID and the files I submitted got deleted. I was told I could make it up the second semester but I switched sports because it was too close contact. Is this reasonable enough to explain? How should I explain it?

Secondly, I received two C's in Geometry that year with the reset being all A's and one B. I then dropped to regular for the rest of my years receiving all A's. Should I explain this too? I don't want to sound like I am excusing it rather I learned math is not my strong suit.