Ralph conducted an experiment to study the effect of temperature change on the heart rate of Daphnia, transparent aquatic invertebrates commonly known as water fleas. Ralph heated three
different beakers of water containing Daphnia to a different temperature: 30°C, 32°C, and 34°C.
He put a drop of water from each beaker on a slide mount. He then used a microscope to observe
Daphnia in each sample. He counted the number of heartbeats in one minute and averaged his
results. Which of the following could be a step in a replication of this experiment?

c. Ralph's classmate observing Daphnia in water at 30oC, 32oC and 34oC

Explanation:

When we talk about replication, we actually mean, repetition of a scientific procedure carried out by another scientist and obtaining the same results as he/she previously did.

Replication is carried out under identical conditions as the first scientist did. If Ralph's classmate wants to replicate Ralph's work, then identical temperature conditions of 30oC, 32oC and 34oC must be used, hence the answer above.

explanation: it gains negative electrons, therefore becoming negatively charged. as charge cannot be created, nor destroyed, only transferred, this leaves the wool positive. now that they have opposite charges, the two items attract.