The presence of stromatolites in some very old rocks can scientists determine the absolute age of those rocks back to about

What was dr. willem johan kolff’s first step in using the scientific process to invent the hemodialysis machine? he built the machine and tried it with various patients, collecting data about its effectiveness. when a patient’s kidneys failed, he wondered if it would be possible to perform kidney functions with an external machine. he researched and collected data about numerous patients who exhibited symptoms of kidney failure. he drew conclusions from studies of various symptoms of kidney failure, and drew a design for the ideal external blood-processing machine.

Researchers want to use edna to look for an invasive species in the water which of the steps would be likely do last

In which situations is the principle of cross-cutting relationship useful in determining relative age?