What would happen if the plasma membrane breaks down

Which is not a characteristic of the animal kingdom? a. they include both vertebrates and invertebrates b. their skin is covered with hair or fur c. they are heterotrophs d. they are eukaryotic

Will someone me with this.. specialized cells which perform a particular function form: tissues organs or organism

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