Complete the article below with the correct form of the verbs in brackets. Use the first conditional. In gaps 4 and 6, use a modal verb to make the prediction less certain.
Some animals, like lizards and worms, have an amazing ability to grow new body parts if they lose them. Salamanders can grow new legs and some worms can re-grow every part of their body, including their head! If scientists 1___________ (can) discover how this happens, in theory it 2___________ (be) possible to re-grow human body parts too. Very few scientists are working on this problem now, but if governments 3___________ (start) to spend more money on research, then this dream 4___________ (become) a reality. Amazingly, some worms have no limit on lifespan, as they continually re-grow their bodies as they age. So if we 5___________ (learn) to repair human limbs and organs, it 6___________(be) possible to prevent us from dying. But that is a long way in the future.
1. can
2. will be
3. start
4. may become
5. learn
6. may be