Question

Which planet has abundant surface water and is known to have life? A) Mars C) Earth B) Jupiter D) Pluto

Short answer

The correct answer is Earth.

Step-by-step solution

Identify Unique Features of Each Planet

To solve this exercise, we first need to recognize the unique characteristics of each planet mentioned. Mars is known for its red dust and evidence of ancient water channels. Jupiter is a gas giant with no solid surface, marked by its massive storms like the Great Red Spot. Pluto, now considered a dwarf planet, has a surface of ice and rock. Earth is the only planet known to have vast water bodies like oceans and is the only one confirmed to support life.

Match the Features to the Question

The question asks for the planet that has 'abundant surface water' and is 'known to have life'. Among the planets listed, Earth is recognized for having large bodies of water, including oceans, seas, lakes, and rivers. It is also the only planet confirmed to have life forms, ranging from microscopic bacteria to complex animals.

Choose the Correct Option

From the analysis, Earth's features align perfectly with the conditions mentioned in the question: abundant surface water and the presence of life. Thus, the correct answer should be Earth.

Key concepts

Surface Water

Surface water is a vital component of Earth's ecosystem. It primarily includes all the water that collects on the surface of the planet. This can be in the form of oceans, seas, lakes, rivers, and even small ponds. The vast surface water bodies are crucial for a variety of reasons:

• They help regulate the Earth's climate by absorbing solar heat and distributing it via currents.
• They support a diverse range of life forms, from tiny plankton to large marine mammals.
• They are essential for human activities such as agriculture, drinking, and industry.

Earth is unique in our solar system because its surface is about 71% water-covered, mainly because of its moderate temperature range. This supports liquid water, which is rare elsewhere in the solar system. Water in liquid form is necessary for life as we know it, offering a habitat, transportation medium, and facilitator of biochemical reactions.

Life on Earth

Life on Earth is astonishingly diverse and complex. Earth is the only planet in our solar system where life is known to exist. The presence of life distinguishes Earth from other planets, thanks to several supportive factors:

• It has a stable climate and atmosphere containing essential gases like oxygen and carbon dioxide.
• It has liquid water available, crucial for all known forms of life.
• It receives the perfect amount of sunlight for photosynthesis, enabling plants to grow, which form the basis of most life systems.

Life on Earth ranges from the simplest single-celled organisms to highly complex organisms such as mammals, birds, and humans.
Photosynthesis and cellular respiration are crucial processes that sustain life, where organisms exchange energy and gases with their environment. This continuous interaction ensures the maintenance of ecosystems and life cycles that flourish on Earth.

Planetary Characteristics

Planetary characteristics are those attributes that make a planet unique. Each planet in our solar system has features influenced by its size, composition, distance from the Sun, and atmosphere:

• Earth is a terrestrial planet, meaning it has a rocky surface and a layered structure with a crust, mantle, and core.
• It possesses an atmosphere rich in nitrogen and oxygen, essential for sustaining life.
• Its distance from the Sun places it in the 'habitable zone,' allowing surface temperatures to maintain water in liquid form.

These characteristics combine to create environments.
Unlike gas giants like Jupiter, which lack solid surfaces and have atmospheres composed mainly of hydrogen and helium, or icy dwarf planets like Pluto that reside on the fringes of the solar system. Earth's features make it a haven for life, and studying these characteristics helps scientists understand the uniqueness of our planet and the possibilities of life elsewhere.