Questions & Answers about Хребет підтримує голову.
Here хребет means the spine, backbone, or spinal column.
A learner should know that хребет can also mean a ridge (for example, a mountain ridge) in other contexts, but in this sentence it clearly means the spine/backbone because it is connected with голову (the head).
It is a masculine singular noun in the nominative case, because it is the subject of the sentence.
Because голову is in the accusative case, not the nominative.
- голова = nominative singular, used for the subject
- голову = accusative singular, used for the direct object
In this sentence, the spine is doing the action, and the head is receiving the action:
- Хребет = subject
- підтримує = supports
- голову = direct object
So Ukrainian changes голова to голову.