Matthew notices that if he walks barefoot on blacktop pavement, his feet get much hotter than if he walks barefoot on grass or dirt. he wants to determine if the amount of blacktop pavement in a city will affect the overall temperature of the city. his hypothesis states that because the pavement absorbs heat from the sun, a city with more pavement will have a higher temperature. matthew uses a map to measure the number of miles of pavement within the limits of his hometown. he then records the temperature outside of his house to see how it varies each day for one week. he asks his friend in the next town to complete a similar experiment. once the data is collected, he concludes that the hypothesis is not supported. 1. what are the major flaws in matthew's experimental design? what are the strengths of the experimental design? explain each in detail using terms from the lesson. 2. this experiment is not able to support matthew's hypothesis. suggest specific improvements that will allow the experiment to more effectively test the given hypothesis. explain why these changes are improvements.

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.