Answer:
The word 'that' is a common word in English that is used in many different manners. Did you notice the use of 'that' in the first sentence? In this case, 'that' was used as a relative pronoun as a compliment. Often 'that' can be used or left out of a sentence entirely.
The word and term 'it' can be used for either a subject or an object in a sentence and can describe any physical or psychological subject and/or object. The genitive form its has been used to refer to human babies and animals
In the short story The Metamorphosis by Franz Kafka he lines reveals that:
Gregor does not want to leave.
The speaker is narrating in the third person concentrating mainly on the feelings, thoughts, and actions of Gregor Samsa in an unchanging and flat tone.