Match each stage to its correct description:

Stages:

1. Nebula
2. Red Supergiant
3. Neutron Star
4. Black Hole

Descriptions:

• A: A highly dense core of nucleons remaining after a supernova.
• B: An object with gravity so strong that even light cannot escape.
• C: A cloud of interstellar dust and gas.
• D: A massive star that has expanded and cooled as it depletes hydrogen in its core.

Which stage in the lifecycle of a massive star immediately precedes a supernova? Select from: red giant, red supergiant, white dwarf, black dwarf.

What nuclear process produces the outward radiation pressure that prevents a main sequence star from collapsing under gravity? Select from: combustion, fission, fusion, alpha decay.

Complete the sentence to describe the forces acting on a star during its stable main sequence stage. Select from: equal to, greater than, less than.

"The inward gravitational force is ____________________ the outward radiation pressure."

Consider the two nuclear processes represented below:

• Equation A: $n+{}_{92}^{235}U\to {}_{54}^{140}Xe+{}_{38}^{94}Sr+2n$
• Equation B: ${}_1^{2}H+{}_1^{3}H\to {}_2^{4}He+n$

Which equation shows nuclear fusion? (Answer A or B)

Which equation shows nuclear fission? (Answer A or B)