The endoplasmic reticulum can either be smooth or rough, and in general its function is to produce proteins for the rest of the cell to function. The rough endoplasmic reticulum has on it ribosomes, which are small, round organelles whose function it is to make those proteins.
Answer:
Earthquakes
Explanation:
This would happen because we have devices such as seismographs to record the motion of the ground during an earthquake. Without that, we wouldn't know how big the earthquake is and how to prepare for survival.
Usually the average growth cycle of eyebrows is 5 to 7 weeks, but it can be shorter or longer depending on various factors such as, your age, metabolism, and weight.