Explain why the cell membrane is said to be semi-permeable?

The term semipermeable means to allow some substances through and prevent others from passing. The cell membrane is semipermeable because it prevents harmful toxins from entering and damaging the cell. At the same time, the cell membrane allows nutrients and other helpful substances through. In this way, the cell membrane is like a security guard of the cell.

satellites are frequently used to make observations of the orbit on earth