An experiment was designed to investigate the effect of caffeine on the rate of heartbeat of fruit flies. Two populations of fruit flies were grown in a lab. Both
populations were raised drinking the same water and the same type of food. Both
populations were exposed to the same amount of light and temperature at 20
degrees Celsius. The fruit flies' heartbeats were then monitored at two hour
intervals. The fruit flies of population one were given caffeine five minutes before
their heartbeat was checked. The flies of population two were not given any
caffeine.
Which of the following is a controlled variable in this experiment?
temperature
caffeine
heart rate
experimental group

air, water, heat and noise pollution can all be caused by producing and using technology. consuming resources - non-renewable resources, including precious metals like gold, are used to make technology

21 stacks

step-by-step explanation:

divide 630/30

21 stacks

enjoy!

sheep is a herbivore animal whereas grasshopper belongs to the class chordates but both of them feed on greens.  

if grasshopper and sheep feeding on a pasture land, i do not think both of them will have any impact on each other. however, the number of the species can make difference. since sheep feed on greens, there is a possibility there left no pasture land for the grasshoppers or they may get extinct.

srxdctfvygbuhinjmok,plkmojnhbgvfctdrft6gyfcgvhbuinjok