Are dogs better pets than cats? How many stars are in the universe? In what type of light will a plant grow best? How many organisms have lived on Earth?
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Which question can be answered by scientific experimentation and observation?
Possibilities:
- Are dogs better pets than cats?
- How many stars are in the universe?
- In what type of light will a plant grow best?
- How many organisms have lived on Earth?

In what type of light will a plant grow best?