The Lamb is featured in the volumes called Songs of Innocence. This particular poem happens to be a child's expression. Children are supposed to be innocent, hence the tone.
Notice that the poem takes the form of a question and answer. Children by nature ask a lot of questions. The child in the poem is portrayed as naive and clever.
A lamb, especially in religious circles is used to portray innocence. Hence its introduction into the volume. One of the lines of the poem which depicts childlike and innocent curiosity reads:
Little Lamb who made thee?
Dost thou know who made thee...
The tone of a story, or poem, expresses the feeling that is intended by the author in relation to the subject matter.
A tone in a story or a poem maybe:
Learn more about Tones in the link below:
https://brainly.com/question/12176973