Answer:
"However, chores are building blocks for a firm foundation."
Explanation:
A metaphor is where one thing is described / compared to another thing, without the use of words such as "like" or "as". It is where one thing is described by directly referring to another.
In this case, "chores" are not actual "building blocks", but are described as being like them, by directly referencing them as building blocks, but without the use of words such as "like" or "as".
Hope this helps!
NOTE: If there is a word such as "like" or "as" (e.g. He was like a lion), than it would be a simile.
