Charlie hypothesizes that if he adds earthworms to a compost pile, it will decompose twice as fast as a compost pile without earthworms. which of the following steps could compromise his experiment?
start two compost piles at the same time with the same materials.
add earthworms to one compost pile.
add decomposing bacteria to the other compost pile.
rate the level of decomposition in each compost pile every week.
report his results.
a.
step 1
b.
step 4
c.
step 2
d.
step 3

Which of the following scenarios is an example of the bottleneck effect? answers a in south africa, much of the afrikaner population is descended from a small number of dutch colonists. in this population, this is an unusually high frequency of pseudoxanthoma elasticum (pxe), an elastic tissue disorder. b four white-tailed deer are introduced to a park in finland. thirty years after their introduction scientists compare the genes in the population and find that there is no variation. c during the industrial revolution, london's air became filled with soot. as a result, birds started eating more of the lighter moths because they were easier to spot than their darker counterparts. over time, the moth population changed so that there were more darker moths than lighter ones. d 10% of the population of american alligators in an area have the recessive trait albinism. a massive flood results in the death of 80% of the population. of the remaining population, 60% have the recessive trait of albinism.

When plants use sunlight to make food, the energy of sunlight is

What are some natural processes that represent physical and chemical changes?