ANSWER: Touch.
The composer refers to hearing through the "clap of lightning" etc. So hearing is one of the senses included in the poem.
The composer refers to sight through "resembles the savannah" etc. So sight is one of the senses included in the poem.
The composer refers to smell through "fragrance" etc. So smell is one of the senses included in this poem.
Therefore, the answer must be touch.
Hope this helps! :)
Have a lovely day! <3