7. A rock has three minerals in itOne of them, quartz, has a hardness of 7 The secondfeldspar, has a hardness of 4. The third, biotite, has a hardness of 2.5. What is true about the hardness of rock?

How do living things obtain phosphorus

Which kind of mutation has occurred when the codon for an amino acid is changed to a stop codon? a. a silent mutation b. a missense mutation c. a frameshift mutation d. a nonsense mutation

Which of the following is an example of competition a. the leaves of a tree prevent a small shrub from getting sunlight. three species of birds feed a different heights in the same tree. b. three species of birds feed at different heights in the same tree c. zebra and giraffe’s feed on different grassland plants d. cats living in two different homes eat the same brand of cat food.