A field biologist observed and recorded the ground squirrel population in a forest ecosystem over a 40 year period. During which years is the squirrel's ecosystem most stable?
A)
years 1-9
B)
years 10-30
years 31-37
D)
years 38-42

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.

Ecologist have observed a sharp increase of sulfur dioxide in the air . what might be a possible consequence of excessive sulfur dioxide in the air ? a. acid rain b. ozone layer depletion c. ozone layer hole d. increase in sea levels

You see a white marker with an orange circle and black lettering. what does this marker tell you