The answer is D vertebrates <span />
It is not all of the above because c is incorrect i dont think a is right either so i would go with b good luck!
To my mind, the correct answer is ( C ) It most likely takes practice to learn to use a ReWalk. Despite the fact that this device helps disabled people to have a more comfortable and normal life style, it seems that it takes practice to learn to use it. It can be inferred when the author describes how to use in the second paragraph. Besides, the author states that the device requires some effort from the person in order to make it function properly (3rd paragraph).
Can I see the poem? It would help me able to answer