I'm pretty sure you would put "Leo" in the blank space because the verb "leer" means to read and the sentence prior to the blank space says "the magazine 'Cosas (or Things)' is my favorite. I read it every month. Hope this helps!
An experiment trying to decide what kind of soil do plants like more
They are an important connection to the past
awnser: c because the other words (Various and Varies) are not words