The 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. I and IV only C. II and III only D. I, II, and III only

The transport tubes from food came down the plant are called?

Temperatures in ponds and lakes vary by season. select the best answer from the choices provided t f

Drag each tile to the correct box. the body monitors the levels of oxygen in the blood to regulate breathing. isabel is running in a marathon and is near the finish line. she feels out of breath. how will her nervous system work to generate a reaction? arrange the tiles in chronological order. isabel's breathing rate increases. sensory receptors in the arteries detect low oxygen levels. the brain sends signals through motor neurons. sensory neurons generate an impulse. the central nervous system relays an impulse to certain brain regions.