Its Is used for repetition AND summary
Mammals (Mammalia) are a class of vertebrate homeothermic amniotes (of "warm blood") that possess milk-producing mammary glands with which they feed the young. Most are viviparous (with the notable exception of the monotrematas: platypus and echidnas). A clear example of a mammal is man and his best friend, the dog.
This should not be included in the notes, because it is scientifically approved that mammals have the capacity to produce milk and give this food to their young, which is vital for humans or dogs as in the example
The answer is <em>swinging through the air</em>.
A dangling modifier is a word, phrase or clause which is misplaced or inappropriately distant from the word it modifies. As a result, it produces confusion and ambiguity.
In this example, it is not clear whether the children or the acrobats are "swinging through the air." The sentence is open to more than one interpretation and has a double meaning.