Among the following major planets in our solar system, which one is often referred to as the green planet because of its bluish green appearance?

Introduction / Context:
This basic astronomy question focuses on the popular nicknames of planets based on their visual appearance. Knowing which planet is called the green planet helps students recall distinguishing features of different planets in the solar system, which is a standard topic in school level science and general knowledge exams.

Given Data / Assumptions:
- The options include Pluto, Venus, Uranus, Mars and Neptune.
- The question asks which is known as the green planet.
- We assume the usual school level descriptions based on telescopic and spacecraft images.

Concept / Approach:
The outer planet Uranus appears bluish green due to the presence of methane in its atmosphere, which absorbs red light and reflects blue and green wavelengths. This gives Uranus a characteristic greenish or cyan colour, leading to the nickname green planet. Mars appears red, Venus appears bright yellowish white, and Neptune appears deep blue.

Step-by-Step Solution:
Step 1: Recall colour based nicknames of planets: Mars as the red planet, Neptune as the blue planet and Uranus as a bluish green planet. Step 2: Note that Venus is often called Earth twin or evening star, not the green planet. Step 3: Recognise that Pluto is now classified as a dwarf planet and is not typically called the green planet. Step 4: Conclude that Uranus, with its bluish green appearance, matches the description green planet.

Verification / Alternative check:
To verify, visualise standard textbook images or models of the solar system. Mars is clearly shown as red due to iron rich dust, while Neptune is deep blue. Uranus is the only planet shown with a cyan or greenish blue colouring. Remembering that methane absorption creates this colour provides an additional scientific check.

Why Other Options Are Wrong:
Pluto is wrong because it is a dwarf planet located in the Kuiper belt and does not have a common green planet nickname.
Venus is incorrect; it is known for its thick cloudy atmosphere and is not green in appearance.
Mars is wrong because it is commonly called the red planet due to its rusty surface.
Neptune is incorrect as it is famous for its deep blue colour, not green.

Common Pitfalls:
Students sometimes confuse Uranus and Neptune, since both are outer gas giants with bluish colours. Others may guess Venus or Pluto simply because they are familiar names. Remembering the specific colour nicknames, such as red for Mars, blue for Neptune and greenish for Uranus, helps avoid these mistakes.

Final Answer:
Hence, the planet referred to as the green planet is Uranus.