If you don't wash the thermometer, residual NaOH will react with the HCl solution. This is a highly exothermic reaction and will change the temperature of the solution, and thus throw off your measurement.
Bears are omnivores (and scavengers), meaning they eat both plants and animals.
it can be both a primary consumer (if it eats plants) and secondary & tertiary consumers (if it eats a plant-eating animal). so it depends on what it eats.
Answer:
The oxidation number of strontium is +2.
Explanation: