Which of the following statements is true about electromagnetic waves?

Electromagnetic waves are unique in that they do not require a medium to propagate. This means they can travel through a vacuum, such as space, where there is no air or any other material. This characteristic sets them apart from mechanical waves, which need a medium (like air, water, or solids) to transmit energy. For instance, light from the Sun reaches Earth through the vacuum of space, demonstrating that electromagnetic waves can indeed travel where no matter exists.

The idea of electromagnetic waves typically being longitudinal waves is also incorrect. In fact, they are transverse waves, which means their oscillations occur perpendicular to the direction of wave propagation. This confusion often arises because sound waves, which are mechanical and require a medium, are indeed longitudinal.

While electromagnetic waves can be influenced by gravitational fields, this effect does not pertain to their foundational ability to propagate through a vacuum. The intricate relationship between electromagnetic waves and gravity becomes relevant in more advanced physics, such as General Relativity, but it doesn't alter the fundamental nature of how and where they propagate.