Variables worksheet bryce heard that when microwave popcorn is stored at different temperatures it will have an effect on the number of kernels left after popping. to test this, he designed an experiment. he purchased 12 packets of the same kind of popcorn. he warmed 4 packets under a heat lamp to a temperature of 40 degrees celsius, he left four packets at room temperature at 20 degrees celsius, and the other four packets were placed in the freezer at -6 degrees celsius. he then microwaved each packet, for 1 minute, and recorded the data. directions: underline the control group highlight the experimental group independent variable: dependent variable: controls (constants):

Compare the composition of the moon's surface with the composition of the earth's surface.

Which of the following statements about archaea and bacteria is true? a. neither is single-celled. b. they both have nuclear membranes. c. neither reproduces by binary fission. d. they both lack a nuclear membrane.

Rease is an enzyme used by plants to break down urea (a nitrogen-containing compound) into carbon dioxide and ammonia. urease urea > > > carbon dioxide and ammonia ammonia is broken down by plants into a nitrogen source plants need to grow. thus, plants could not use urea as a nitrogen source unless it was first converted to ammonia. in soybean plants there are two different kinds of urease, one produced in the seeds and the other produced in the leaves of the plant. three types of soybean plants were used in a set of experiments: normal soybeans and two mutant strains, one lacking the urease in the seeds only (strain 1) and one lacking urease in the leaves only (strain 2). experiment 1 separate areas in a field were planted with normal, strain 1, and strain 2 soybeans. all types of soybeans appeared to grow, flower, and produce seeds equally well. there were no externally detectable differences among the strains. experiment 2 small pieces of plant leaves of equal weight were obtained from each type of soybean plant and separately placed on media in culture dishes. tissue growing in this way will become an unorganized clump of cells referred to as callus. to provide a controlled nitrogen source, half the tissue samples of each type were placed on media containing urea, and the other half of the samples were placed on media containing ammonia. after 30 days, the weight gain for each of the callus samples was determined. results are shown in the table below.