Question

1. drag and drop the terms to complete the diagram of the life cycle of a massive star.

star - forming nebula
massive star
supernova
choices
black hole
red supergiant
neutron star

Explanation:

Step1: Identify the life cycle stages

The life cycle of a massive star starts with a star - forming nebula, then becomes a massive star. After the massive star, the next stage is the red supergiant (this is the stage after the massive star before the supernova). So the middle dashed box (connected to massive star) should be filled with red supergiant.

Step2: After supernova

After a supernova, a massive star can either become a neutron star or a black hole. The bottom dashed box (connected to supernova) can be neutron star or black hole, and the top dashed box (connected to the middle box) - wait, let's re - trace. The correct order is: star - forming nebula → massive star → red supergiant → supernova → neutron star/black hole. So the middle box (between massive star and supernova) is red supergiant. The bottom box (after supernova) can be neutron star or black hole, and the top box - wait, the diagram structure: the arrows are star - forming nebula → massive star → [middle dashed] → supernova → [bottom dashed] and [middle dashed] also connects to [top dashed]? Wait, no, let's look at the choices. The choices are black hole, red supergiant, neutron star. So the correct filling:

• The middle dashed rectangle (connected to "massive star"): red supergiant (because massive star evolves into red supergiant before supernova).
• The bottom dashed rectangle (connected to "supernova"): can be neutron star or black hole. Let's assume the standard life cycle: massive star → red supergiant → supernova → if the remnant mass is between 1.4 and 3 solar masses, neutron star; if more than 3 solar masses, black hole. But from the diagram, after supernova, one of the dashed boxes (bottom) and another (top). Wait, maybe the top dashed box is connected to the middle (red supergiant) and the bottom to supernova. Wait, no, let's do step by step:

1. The box between "massive star" and "supernova" is "red supergiant" (so drag "red supergiant" to the middle dashed box).
2. After "supernova", we have two possible outcomes: "neutron star" and "black hole". So drag "neutron star" to one of the remaining dashed boxes (say bottom) and "black hole" to the other (top), or vice - versa. But the main stage after massive star is red supergiant, then supernova, then neutron star or black hole.

Answer:

• Middle dashed box (connected to massive star): red supergiant
• Bottom dashed box (connected to supernova): neutron star (or black hole)
• Top dashed box (connected to middle box): black hole (or neutron star)

(The specific dragging: drag "red supergiant" to the middle dashed rectangle, drag "neutron star" to the bottom dashed rectangle, drag "black hole" to the top dashed rectangle or adjust based on the exact diagram connections, but the key stage after massive star is red supergiant, after supernova are neutron star and black hole.)