Thin, flexible barrier around a cell; regulates what enters and leaves the cell
- contains the cytoplasm (all interior cell organelles and the cytosol) - allowing the chemical reactions in the cell to occur
<span>- semipermeable (or selectively permeable) - allows certain substances in, keeps others out </span>
<span>- offers limited protection</span>
The answer is D as a watch mean to be careful and a warning is go inside and wait.
An emergency appointment is to deal with a life-threatening medical issue. For example, someone having an allergic reaction. An urgent appointment is for a medical issue that is time sensitive, but can wait a little while. For example, a sprained ankle.