NEET Biology NEET PYQ-Chemical Coordination

Which of the following is used in the treatment of thyroid cancer? [AIPMT 2002]

A) I131

B) U238

C) Ra224

D) C14

Correct Answer: A

Solution :

[A] Radioactive iodine administered to patients suffering from thyroid cancer.

Era		Events
a. Precambrian	(i)	Approximate origin of Earth.
	(ii)	Oldest definite fossils known (prokaryotes).
	(iii)	Oxygen begins accumulating in atmosphere.
	(iv)	Oldest eukaryotic fossils.
	(v)	Origin of first animals.
b. Paleozoic	(i)	Origin of most invertebrate phyla; diverse algae.
	(ii)	First vertebrates (jawless fishes); marine algae abundant.
	(iii)	Diversity of jawless vertebrates; colonization of land by plants and arthropods; origin of vascular plants.
	(iv)	Diversification of bony fishes; first amphibians and insects.
	(v)	Extensive forests of vascular plants; first seed plants; origin of reptiles; amphibians dominant
	(vi)	Radiation of reptiles; origin of mammal like reptiles and most modern order of insect; extination of many marine inverte-braters.
c. Mesozoic	(i)	Gymnosperms dominate landscape; first dinosaurs and mammals.
	(ii)	Gymnosperms continue as dominant plants; dinosaurs dominant; first birds.
	(iii)	Flowering plants (angiosperms) appeal, dinosaurs and many groups of organisms become extinct at end of period.
d. Cenozoic	(i)	Major radiation of mammals, birds and pollinating insects.
	(ii)	Angiosperm dominance increases; further increase in mammalian diversity.
	(iii)	Origins of most modern mammalian orders, including Apes.
	(iv)	Continued radiation of mammals and angiosperms.
	(v)	Ape like ancestors of humans appear.
	(vi)	Ice ages; humans appear.