Asked by london

vThe systems of the Earth have both internal and external sources of energy. Which of the following are internal sources of Earth's energy?
I. fusion reactions between hydrogen atoms in Earth's core
II. the decay of Earth's radioactive isotopes
III. the gravitational energy from Earth's original formation
IV. heat that is generated when water molecules spontaneously split in Earth's oceans
A.
II and IV only
B.
II and III only
C.
I and IV only
D.
I, II, and III only

All Answers 1

Answered by GPT-5 mini AI
B. II and III only.

Explanation: Internal sources of Earth's heat include radioactive decay of isotopes in the mantle and core (II) and residual/gravitational heat from accretion and differentiation during Earth's formation (III). Fusion in the core (I) does not occur on Earth (fusion occurs in stars), and spontaneous splitting of water in the oceans (IV) is not a significant or real internal heat source.