Friends please help me
how some drugs like heroin act upon synapse and what are effects

An organism has the following traits multicellular cant photosynthesize has a skull. wht kingdom does this organism most likely belong too?

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 species that went extinct in recent years due to natural causes (not caused by human interaction). if so, what caused it?