What special precautions must be taken when using the oil immersion (100x) objective?

list the reagents used in the IMViC tests and what they detect

1. What is the purpose of adding immersion oil when using the 100X objective?

Two students independently determine the volume of water delivered by a 10.00-mL pipet. Each student takes 8 measurements, then computes the average volume delivered and the standard deviation. The results are tabulated below.       Average St. Dev.   Student A 10.4 mL ±0.7 mL   Student B 10.00 mL ±0.02 mL   Which statement best describes the results? 1)A: good precision, poor accuracy. B: poor precision, good accuracy. 2)A: poor precision, good accuracy. B: good precision, poor accuracy. 3)A: poor precision, poor accuracy. B: good precision, good accuracy. 4)A: good precision, good accuracy. B: good precision, good accuracy. 5)A: poor precision, poor accuracy. B: poor precision, poor accuracy.