It applies to chemical reactions in general, including those that are involved in biological processes. The reactions that cover life proceed, for the most part, for exactly the same reason my pen falls to the floor - the resulting state is a lower energy state than what you started with.
This is basic freshman chemistry - there's nothing magic about biochemistry that makes it operate by a different set of rules than any other sort of chemistry. You might as well ask what force "compels" a match to burn when struck or a piece of iron to rust when exposed to oxygen.
Only those specific reactions utilizing the 4 amino acids in DNA seem compelled to reporduce and create ever more complex and ever more energy dependnent constellations of reactivity.
DNA is composed of nucleotides, which code for twenty different amino acids. Personally, I think it's remarkable that only silicon atoms seem compelled to make silicon dioxide. Carbon, on the other hand, is capable of forming concatenated chains - making complex molecules out of nothing more than methane and a few odds and ends is not particularly difficult. How boring.
Gravity fits the description of a "spirit", it cannot be seen, heard, felt, tasted etc ...it cannot be measured directly. We can only measure the force it applies to things that we can then measure directly.
That doesn't even remotely make sense - gravity is not some invisible elf that somehow exerts a force upon you, it is a force, in and of itself. What difference do you think you're measuring if you take a known mass and weigh it here on earth, and then weigh it on the moon? Not the mass - that's constant. You're measuring gravity, and quite directly too.
I see. The origins of life are explained by basic Freshman Chemistry.
okay
Ask your biology teacher if he agrees with your above statement.
"Everyone who is seriously involved in the pursuit of science becomes convinced that a spirit is manifest in the laws of the universe -- a spirit vastly superior to that of man." -- Albert Einstein
peace