Question

1. choose the best answer.

clyde tombaugh discovered ____ by comparing two photographs of the same part of the sky.
neptune
pluto
ceres
charon

1. choose the best answer.

once classified as an asteroid, spherical ____ is the only dwarf planet found in the asteroid belt.
ceres
apollo
cassiopeia
perseus

Explanation:

For question 7: Clyde Tombaugh discovered Pluto by comparing two photographs of the same part of the sky. Neptune was discovered through mathematical predictions, Charon is Pluto's moon, and Ceres is a dwarf planet in the asteroid belt (not discovered by Tombaugh in this method).
For question 8: Ceres is the only dwarf planet found in the asteroid belt and was once classified as an asteroid. Apollo, Cassiopeia, and Perseus are not dwarf planets or related to the asteroid belt in this context.

Answer:

1. B. Pluto
2. A. Ceres