On handling Physalia, a representative of phylum Cnidaria, it stimulate nematocysts to release bio-active compound. This compound is of the nature of :
MH SET - 2025, SET Exam - 2025,
Answer: B
The key's answer is haemotoxin.
Physalia (the Portuguese man-of-war) discharges its nematocysts on contact. The best characterised protein in the venom of Physalia nematocysts, physalitoxin, is a large haemolytic protein (it lyses red blood cells) and is lethal to mice, and it makes up a large share of the nematocyst venom protein. That supports a haemolytic, blood-acting toxin as the key.
Neurotoxin is the option a candidate is likely to choose, because the sting is painful and venoms of cnidarians are often described as neurotoxic; the key treats the haemolytic toxin as the answer. The other two options are not what venom studies of Physalia single out as its characterised toxin. The key's reading is followed here.
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