On a warm summer day, a severe storm happens, and a tornado forms. Which layer of the atmosphere is experiencing this storm?

troposphere
stratosphere
mesosphere
thermosphere

Which strategy is an example of how companies may upgrade themselves to meet changing customer preferences? a. doing door-to-door sellingb. using billboards to advertise the productsc. making online shopping services availabled. giving discounts on products

The concept of keystone species is controversial among ecologists because most organisms are highly interdependent. if each of the trophic levels is dependant on all others how can we say one is most important

Is there any solid scientific evidence that humans have been cloned?