Achemist is study the effects of minerals on plant growth. she knows that phosphorus stimulates pant growth. she decides to test the effects of various phosphorus concentration on plants every 5 days over a 20 day period what is the independent variable?

Football players often sustain lateral blows to the extended knee. which of the ligaments is (are) damaged as a result? a. suprapatellar b. oblique popliteal and extracapsular ligament c. medial collateral, medial meniscus, and anterior cruciate d. arcuate popliteal and the posterior cruciate

Which best describes how the common cold spreads in the human body? a bacteria burst out of normal cells killing them b viruses replicate inside respiratory cells c bacteria inject dna into normal cells d viruses insert dna into bacteria

Some birds look for food near cattle and other livestock. the movement of the cattle churns up the ground, making insects available to the birds. the cattle appear to be unaffected by the presence of the birds. what kind of relationship exists between the birds and the cattle? o a. parasitism o b. commensalism o c. predation o d. mutualism