Read the passage below: A volcano erupted along a mountain side. After the eruption, the ground was basically just rock. Lichens and mosses began to grow on the rock and began to
break down the rock to form soil. Small grasses begin to take root and start to grow also.
Smaller shrubs come next. Squirrels and rats moved in to dig holes in the soil which allowed
plants to grow. After several years, trees take root and grow where there once was only rock.
Why is this an example of Ecological Succession AND what type of succession is this (primary
or secondary)? Provide evidence to support your answer.

Aresearcher designed an investigation to test what effect eating different types of food would have on blood insulin levels. she selected 10 male subjects who were all 25 years of age and in good health. the experiment took place over 3 days. at 8: 00 a.m. on each day, the subjects ate a meal consisting of only 1 type of food. they had their blood insulin levels measured after consuming the meal. on day 1 they ate a high fat diet, on day 2 they ate a high protein diet, and on day 3 they ate a high sugar diel what is the independent variable in this experiment? a the age of the subjects b the blood insulin level c the type of food consumed d the time of day the meal was consumed

What is the main function of the central vacuole in a plant cell? a. absorbs energy from the sun to produce food b. holds water and maintains turgor pressure c. breaks down molecules to release energy d. contains the cell's genetic material

Ascientific idea becomes valid when it is what?