When a diamond and silver are rubbed together, the diamond makes a scratch in the silver. What does this tell you about the two substances?
A. Diamond changes the silver into something else.
B. Silver is hardhs than diamond.
C. Diamond is harder than silver.
D. Diamond and silver have the same hardness.
SUBMIT

Juan and carol were studying invertebrates in biology. they knew that segmented or earth worms preferred a dark, moist habitat. during this lab, they would be investigating the responses of organisms called planaria or dugesia tigrina. these were simple flatworms that still had a one-way digestive system and a very simple nervous system. juan and carol placed the planaria in a petri dish containing cool, distilled water that was partially covered with black paper. they shined a light on the dish. next, they removed the paper and placed a small amount of chicken liver at one end of the dish. they added a few large salt crystals to the water. finally, they added drops of hot water to the cool water in the petri dish. their results can be seen in the data table. according to their experiment, all but one conclusion is valid.

You will create a molecular clock model for an arthropod gene. follow these guidelines to make your model: . your timeline will span from 90 million years ago to the present. the common ancestor in your model is an arthropod that lived 90 million years ago. the gene that you'll track codes for a protein in the species venom . the dna sequence youll track contains 10 nitrogen bases. you can choose the order of the bases and where the mutations occur. this gene mutates at a rate of approximately 0.76 base pairs every 17.1 million years. to build your model,/ calculate the estimated time period it takes for 1 base pair to mutate. the first time period will only show the common ancestor. at the beginning of the second time period, three lineages will diverge from the common ancestor, each with a different mutation in their gene sequences. the first and third descendant species will survive for the rest of the timeline. the second descendant species was extinct 50 million years ago. calculate how long it will take for one full base pair mutation to occur. explain your reasoning by constructing a mathematical equation

Clara wrote the following hypothesis for an experiment about acidophilic bacteria. bacteria cells will stop dividing in a basic (alkaline) environment because of the high ph. which statement is the best way to restate the hypothesis so that it is more specific? growing acidophilic bacteria in some environments will cause the cells to stop dividing because of ph. if the ph of their environment is changed, acidophilic bacterial cell division will be affected. if the environment of acidophilic bacterial cells becomes alkaline, the bacteria will stop dividing. the more alkaline an environment, the less cell division will occur in bacteria.