Choose the alternative that fills in correctly and respectively the...

Choose the alternative that fills in correctly and respectively the blanks in the sentences below with the correct modal verb.

Notion of an 'event horizon', from which nothing _____________ ¹ escape, is incompatible with quantum theory, physicist claims.

The defining characteristic of a black hole _____________ ² have to give, if the two pillars of modern physics – general relativity and quantum theory – are both correct.

Most physicists foolhardy enough to write a paper claiming that “there are no black holes” – at least not in the sense we usually imagine – ____________ ³ probably be dismissed as cranks. But when the call to redefine these cosmic crunchers comes from Stephen Hawking, it’s worth taking notice. In a paper posted online, the physicist, based at the University of Cambridge, UK, and one of the creators of modern black-hole theory, does away with the notion of an event horizon.

But on analysing the situation in detail, Polchinski’s team came to the startling realization that the laws of quantum mechanics, which govern particles on small scales, change the situation completely. Quantum theory, they said, dictates that the event horizon _____________ ⁴ actually be transformed into a highly energetic region, or 'firewall', that _______________ ⁵ burn the astronaut to a crisp.