It's possible for an offspring to exhibit a recessive trait even if neither parent exhibits that recessive trait. what must be true about the parents genese for this to occur?

I'm thinking that someone higher up the family tree has to have had the recessive trait, which makes it possible for anyone after them to have it. That or the parents can still be carrying it, because recessive traits aren't always displayed even if they're carried.

the overall balanced equation

6co2 + 6h2o > c6h12o6 + 6o2

sunlight energy

where: co2 = carbon dioxide

h2o = water

light energy is required

c6h12o6 = glucose

o2 = oxygen