Which item creates more than 50 decibels of sound?

Which kind of worm has a closed circulatory system? a planarian b fluke c pinworm d an earthworm

One student group hypothesized that the dry baker's yeast must be alive. the temperature change, odor, and bubble foation, they said, indicated whych characteristic of life

How do you suppose living conditions differ between the country furthest along in the demographic transition compared to the country earliest in the transition? how would living conditions in these two countries affect both birth and death rates?