ACROSS
1 See 27 Down
5 Category 5 hurricane that struck US Gulf Coast in August 2005 (7)
9 Fibrous protein found in claws (7)
10 One of 118, perhaps I, O or U (7)
11 Yellowish form of iron oxide (8)
12 Equiangular polygon (6)
14 Type of long-focus lens (9)
17 Cat-like Madagascan carnivore (5)
18 Wolfgang ___ (1900–58), Austrian physicist (5)
20 Obsolete term for chronic obstructive pulmonary disease (9)
23 Simple sugar, C5H10O5 (6)
24 Lynn ___ (1938–2011), proponent of symbiosis in evolution (8)
28 US space probe that arrived at…
