Question

open - end wrenches
an open - end wrench is identified by its \open ends\. the ends grip a bolt or nut on two faces (or flats). when force is applied to the wrench, contact is made with only two faces (flats), thus less force is transferable to the bolt or nut, compared to a box - end wrench that grips on all faces.
because of its open ends, the wrench can fit onto the bolt or nut from the side, making the open - end useful in situations where space is limited.
the open - end wrench has different sizes on each end. the open - end wrench head is usually at a 15° angle to the handle, enabling an extra 15° of movement when the wrench is turned around on its axis. open - end wrench sizes vary. special tools can be designed using an open - end; providing access to objects that are otherwise difficult if not impossible to reach with a box - end wrench or socket.
1
how can you identify an open - end wrench?
the head of the wrench is usually at a 15° angle.
the ends of the wrench are open.
the size on each end are different.

Explanation:

The text states that an open - end wrench is identified by its "open ends". It also mentions that the open - end wrench has different sizes on each end and the head is usually at a 15° angle to the handle, but the most defining characteristic for identification is the open ends.

Answer:

The ends of the wrench are open.