Final answer:
The Earth is largely composed of elements like oxygen and silicon, making up its crust. It has a solid iron core, a liquid outer core, a rocky mantle, and a crust. Due to its size, composition, and position, Earth uniquely supports liquid water and life.
Step-by-step explanation:
The Earth is an astonishing planet with a complex composition. Ninety-eight percent of the solid matter in the Earth's crust is made of eight elements. The most abundant are oxygen, silicon, and others including aluminium, iron, calcium, sodium, potassium, and magnesium. Oxygen is particularly prevalent, making up 47% by weight and 94% by volume of the crust, whereas silicon accounts for 1% by volume and 28% by weight. The Earth formed about 4.5 billion years ago from a rotating cloud of stardust, which contained the elements that constitute not only our planet but also every living and nonliving thing on it. Our solar system began from the materials left by supernovas and red giants, astronomical events that created the heavier elements such as iron, which is now a key component of our red blood cells. Earth's structure consists of several layers, beginning with a solid iron core, an outer liquid-iron core, followed by a rocky mantle, and the crust. Above these solid and molten inner layers lies a relatively thin atmosphere. These layers were identified by studying the transmission of seismic waves, which provided crucial insights into Earth's interior composition and structure.
Moreover, Earth's diameter is approximately 12,760 kilometers, classifying it as a medium-size terrestrial planet. Its unique position and composition allow it to support liquid water and a range of temperatures conducive to life. Thus, Earth is the only planet we know of in our solar system that supports life, primarily due to its balanced conditions and mixture of elements.