Question

1. which of the following correctly identifies the approximate composition of the universe?

a. 50% hydrogen; 50% helium
b. 75% helium; 25% hydrogen
c. 25% oxygen; 75% lithium
d. 75% of hydrogen; 25% helium

1. which of the following is not a main type of data used to study the universe?

a. redshift of galaxies
b. composition of the earth
c. cosmic microwave background radiation
d. gravitational waves

1. what advances in technology have helped astronomers study the universe?

a. television and microscopes
b. automobiles and airplanes
c. telescopes and space probes
d. mining resources from earths crust

1. which theory is the most widely accepted theory for the origin of the universe?

a. steady-state theory
b. big bang theory
c. multiverse theory
d. cyclic model

Explanation:

1. The universe is mainly composed of hydrogen (about 75%) and helium (about 25%).
2. The composition of the Earth is not a main data type for studying the universe. Redshift of galaxies, CMBR, and gravitational waves are.
3. Telescopes (e.g., Hubble) and space probes (e.g., Voyager) help astronomers observe distant objects.
4. The Big Bang Theory is widely accepted as it explains the origin, expansion, and elements in the universe.

Answer:

1. d. 75% hydrogen; 25% helium
2. b. Composition of the Earth
3. c. Telescopes and space probes
4. b. Big Bang Theory