The non-living factors of the enviroment are rocks, water, and sunlight.
When the effects of genes add up to make the phenotype, they are called additive genes.
Answer:
In uranium-lead dating, for instance, the radioactive decay of uranium into lead proceeds at a reliable rate. Based on the very old zircon rock from Australia we know that the Earth is at least 4.374 billion years old.
And that's how after rounding we know that earth is 4.5 years old.
By the excretory system through the large intestine
