What does effective means?

A(n) __ clause should always be separated from the rest of the sentence by commas

When i was four years old, my dad and i a tree in our front yard. it was a tiny, fragile sapling. he promised me that it would grow tall and strong, but he said that i had to be patient. until i turned 18 years old, dad and i it every year on my birthday. choose the words that correctly fill in the blanks.

Which two sentences in this excerpt from the time machine by h.g. wells suggest that the morlocks possesses a degree of intelligence comparable to that of humans