page 14 23. Eggs of the parasitic liver fluke Leucochloridium paradoxum are found on vegetation and can be eaten by marsh snails, Succinea putris. Inside snails, eggs develop into larvae which move to the ends of their tentacles. The tentacles become swollen and brightly coloured, resembling striped caterpillars. Infected snails become more active during daylight when predatory birds mistake the abnormal tentacles for caterpillars and eat them. The larvae within the tentacles complete their life cycle within the birds’ bodies. Eggs are passed out of the birds in faeces. Which items on the list represent part of the extended phenotype of the parasite? 1 Prey selection by birds 2 Modification of snail tentacles 3 Changed activity of snails 4 Feeding method of snails A 1 and 2 only B 1 and 3 only C 2 and 3 only D 3 and 4 only 24. Which row in the table identifies white blood cells capable of long term survival as a part of immunological memory in mammals? Type of white blood cell B lymphocytes T lymphocytes Phagocytes Natural killers A ✓ ✓ B ✓ ✓ C ✓ ✓ D ✓ ✓