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Answer: C. a balance and a beaker</h3>
Explanation:
A balance would be used to measure the weight, which in turn effectively measures the mass (more or less). Imagine that we have a brick that we know is 1 pound. If we have an object that needs 5 bricks on one side to balance it out, then we know the object is 5 pounds.
The beaker is used to measure the volume. It's basically a measuring cup that you would find in the kitchen.
To get the density, you divide the mass over volume.
For example, if you have a material that has a mass of 100 grams and it's volume is 20 cm^3, then its density is 100/20 = 5 grams per cm^3.
Answer:
The bacteria infected with viruses that had radioactive DNA had become radioactive. The bacteria that had been infected with viruses marked with radioactive proteins were not radioactive.
Explanation:
The rest of the answers:
1.2
2.3
3.2
4.1
5.b
An ecological niche is an organism's specific habitat in an ecosystem.
It is where it lives and feeds, etc.
Answer:
The cell membrane, therefore, has two functions: first, to be a barrier keeping the constituents of the cell in and unwanted substances out and, second, to be a gate allowing transport into the cell of essential nutrients and movement from the cell of waste products.
Explanation: