What will stop if you drink too much alcohol

Explain how paleontologists use trilobite fossils as index fossils for various geologic time periods.

According to theories of how life began, how did early organic molecules begin to separate from the outside world? a: specialized enzymes were required b: chains of amino acids created a barrier c: formation of microspheres or vesicles d: rna catalyzed the formation of membranes

Why has two different alleles for the same trait?