no, it not useless. we still learn Bohr's model in HS n dats almost 200 yr old! while there may be new models, previous one is good for explaining the basics. it is also useful to learn previous model n see how our understanding improves over time.
Answer:
health factors that could harm you or your offspring
Answer: Because of the different wave speed from light and sound. Explanation: There is a major difference between the speed wave of light and sound, light travels at 186, 282 miles per second, and sound can travel at different speeds and its significantly slower so it is easier to measure it
Explanation:
The answer is b. The crest.
Hope this helps!