can a 2x4 wall support a second story

Yes, a 2x4 wall can support a second story, but it depends on several factors. For example, the spacing of the studs, the type of load (live and dead loads), and the quality of construction. If these are all properly accounted for, it can be sufficient.

In most cases, a 2x4 wall can't support a second story. It lacks the necessary strength and stability. Professional assessment and additional support structures would likely be required.

It can. But the strength of the connection between the 2x4s and the foundation, as well as between the 2x4s themselves, is vital. If the connections are weak, it won't support the upper floor well.

Wall and wall were two common terms in architecture. They were different in function and structure. A wall was a city wall or fence built with earth, stone, bricks, and other materials. Its function was to separate space, protect, and bear weight. The walls generally did not have a closed top, so they could climb over them. The wall was a barrier made of earth, stone, bricks, and other materials inside the house. It was tightly connected to the roof or ceiling to separate the inside and outside space. The walls were usually sealed, and one could not climb over them. The definition and difference between walls could be deduced. The walls mainly consisted of bearing walls and non-bearing walls, which served as a protective barrier and space partition. The wall must have sufficient strength and stability, as well as heat preservation, heat insulation, sound insulation, fire prevention and waterproof capabilities. There were many types of walls, and they could be made of a single material or a composite material. A wall was a type of wall, a barrier inside a house. It was connected to the roof or ceiling to separate the inside and outside of the house. To sum up, a wall referred to a city wall or fence built with earth, stone, brick, and other materials to separate space, protect, and bear weight. A wall referred to a barrier built with earth, stone, brick, and other materials inside a house. It was tightly connected to the roof or ceiling to separate the inside and outside space.

Pei Nanwei's original description of Xu Fengnian's support against the wall was in chapter 168 of Sword Snow Stride. In this chapter, Xu Fengnian held his waist with one hand and opened the wooden door with the other. He rubbed his waist and supported himself against the wall as he walked. Pei Nanwei muttered to herself in the room,"What number one in the world? Didn't he still go out with the help of the wall…"