Converting a prairie to a farm field is an example of________.

Exotic species can  become invasive in their new habitat, because of absence of their predators.  They can threaten the native species by competing for their resources, being predators, or bringing disease.

The melting point of a mixture will be [answer1] than either of the substances alone, therefore, it can be concluded that as melting point range [answer2] the purity of the sample [answer3]. 

Primary consumers are

When synthesizing aspirin, 3.012 g of salicylic acid (138.121 g/mol) were used. 2.538 g of aspirin (180.158 g/mol) were recovered. Answer must be to correct significant figures and proper units.   Calculate the theoretical yield of aspirin. [answer1] Calculate the percent yield. [answer2] Calculate the percent error. [answer3]

The majority of the water found on Earth is:  

The formation of bubbles when HCl is added to a magnesium ribbon is a type of chemical change. 

Extinction is the complete loss of a specie

Match the reagent/test for protein, gelatin, calcium, phosphate, and ferric ion in bone. 

 You are evaluating a cross-country runner who has sustained a knee injury. He relates that as he turned a corner while running on a cross country course, he stepped in a shallow hole; his knee was slightly externally rotated. He noted quick swelling in his knee and that the knee seemed to “lock.” With the patient supine and his hip and knee flexed, external rotation of the lower leg on the affected side reveals a palpable “click” as the knee is flexed and extended. Further examination reveals a negative Drawer sign. Based on this information, which of the following conditions is the most likely source of this patient’s complaint?