A scientist observes that even after sterilizing a broth, cell...

Question

A scientist observes that even after sterilizing a broth, cells reappear in the broth over time. The scientist then asks: 'Why do cells reappear in the broth after sterilization?' and designs/conducts an experiment. Considering this, appropriately label each of the following blanks as either a 'prediction, hypothesis or theory.'

________________: Cells will only appear in the broth exposed to a source of preexisting cells.

________________: Cells appear only when preexisting cells grow & divide; therefore, cells only appear in exposed broths.

________________: All organisms consist of cells & all cells come from preexisting cells.

Accepted Answer

Alright. So here we have a practice problem that says a scientist observes that even after sterilizing broth, cells reappear in the broth over time. The scientist then asks the question, why do cells reappear in the broth after sterilization? And then designs and conducts an experiment. Considering this, appropriately label each of the following blanks down below right here as either a prediction, a hypothesis, or a theory. And so notice that we've got each of these 3 blanks down below that correspond with, the, sentence that follows. And so, what we need to recall from our previous lesson videos is that a prediction is an expected outcome of an event, and of course the prediction is really only gonna answer the question to what will happen. Now recall that the hypothesis is going to be a testable explanation for an observation. And so not only will it answer the question to what will happen, but it will also answer the question to why it will happen. And then also recall from our previous lesson videos that the theory is really just a testable and broad hypothesis. And so really the key word here is that it is going to be broad. So keeping this in mind, what we can do is take a look at the first blank here, which says cells will only appear in the broth exposed to a source of preexisting cells. Now this sounds like it's answering the question to what will happen. Cells will only appear in this broth when they're exposed to this, but it does not answer the question to why it will happen. Why is it that the cells will only appear in this broth when it's exposed to pre existing cells? Why? And that why is not fully answered. And so that means that this first one is going to be the prediction. Now moving on to the next blank here, it says that cells will appear only when pre existing cells grow and divide. Therefore, cells only appear in exposed bras. So this part over here, cells only appear in exposed bras, is basically answering the question to what will happen. However, to say that cells appear only when preexisting cells grow and divide, that's answering the question of why it will happen. The cells will appear in the Expros bra because, cells only appear when pre existing cells grow and divide. And so because this one is answering the question to both what and why, it will happen, this will be the hypothesis. And then, of course, last but not least, what we have is this last blank here, which says all organisms consist of cells and all cells come from preexisting cells. And so because it's including all organisms, it's very, very broad, and that means that this will be the theory. And it turns out that this theory here that all organisms consist of cells and all cells come from preexisting cells is actually a basic fundamental theory, that we will introduce in our next video. And so this here concludes, the answers to this practice problem, and I'll see you guys in our next video.

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