Correct Answer : 3.5 billion years
Evidence suggests that life on Earth has existed for about 3.5 billion years. The earliest known fossils on Earth date from 3.5 billion years ago and there is evidence that biological activity took place even earlier - just at the end of the period of late heavy bombardment.
Correct Answer : Neptune
Correct Answer : Cyan
Correct Answer : Cosmology
Correct Answer : Agricultural Pests
Correct Answer : Commensalism
Correct Answer : Metamorphic
Correct Answer : Buffalo
Correct Answer : Skin cancer
Most skin cancers are a result of exposure to the UV rays in sunlight. Both basal cell and squamous cell cancers (the most common types of skin cancer) tend to be found on sun-exposed parts of the body, and their occurrence is typically related to lifetime sun exposure.
Correct Answer : Parent rock
