Answer:
There is no short answer.
Explanation:
The primary difference between the periodic and perpetual inventory system is that the perpetual system keeps track of things from the start to finish continuously while the periodic system divides it into periods and keeps the records at the end of every set period of time.
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Looking at the onion root tip under the microscope you can see large, rectangular cells with visible distinct cell walls surrounding it (cells have a more regular shape because of the wall). Inside the cells, you can notice darkly stained nucleus, large vacuoles at the center and sometimes small granules within the cytoplasm. Looking the onion root tip under the microscope is often the way to observe mitosis. Usually, you cannot see organelles such as mitochondria, ribosomes, rough and smooth endoplasmic reticulum, centrioles and Golgi body as they appear translucent and because are too small to be seen under the light microscope (electron microscope required). Also, chloroplasts are not present in an onion cell because it is not a photosynthetic cell.
Answer:
3) Temperature
4) gill covering opening and closing per minute
5)as temperature rises, the rate of gill covering opening and closing per minute increase until the temperature reaches 27℃ where the rate decreases
Explanation:
4) you can adjust and control the temperature in an experiment
5) you can't control the gill opening and closing rate
Answer:
most common samples used today Blood and Hair
