What happened during the cambrian explosion? a. early chordates began to appear. b. many groups of vertebrate animals became extinct. c. groups of dinosaurs began to evolve into the ancestors of modern birds. d. animals evolved a variety of complex body plans.

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.

In general, characteristics that an organism survive and reproduce become more common in a population over time. what mechanism of evolution cause this change?

Explain why it’s important for scientists to study the sun. list at least two challenges researchers face when examining earth’s nearest star.