HELP PLEASE

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.

Some technological solutions to problems like global warming meet the specific needs and situations of local communities. an example from india involves converting the solid waste from cattle into clean-burning fuel for cooking. this reduces the amount of greenhouse gases, specifically methane and carbon dioxide, released into the environment from wood fires. when evaluating the feasibility of implementing this solution, computer models are used to weigh costs against benefits. what factor is least likely to impact the decision on adopting this technology?

The concept of keystone species is controversial among ecologists because most organisms are highly interdependent. if each of the trophic levels is dependant on all others how can we say one is most important