Answer:
(d). a semipermeable membrane.
Explanation:
The cells of all organisms are covered by a lipid bilayer, known as plasma membrane that separates interior of a cell from its outside environment. The plasma membrane is a semipermeable membrane that allows transport of certain molecules only.
The molecules that can easily pass through plasma membrane are non-polar molecules, such as urea and oxygen or small polar molecules, such as water due to its hydrophobic nature.
The larger substances, such as glucose or charged molecules, such as ions cannot pass directly through plasma membrane. They require transport proteins for their transport and this process is known as facilitated diffusion.
So, the given scenario represents semipermeable nature of plasma membrane. Thus, the correct answer is option (d).
