Explain what improvements are necessary before electrical devices can replace human arms and legs?

When lose an arm or a leg
Answer:
1. Nerve impulse signal integrity and discrimination for neural synaptic interface.2. Artificial muscle (polymer hydogel)3. Artificial bone using nanotechnology to grow as the subject grows this would also apply also to the artificial muscles.

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I saw a woman on Oprah recently who had a bionic arm, so they already exist.

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