The cell membrane

is not a true organelle
contains and protects the cell
is made of a double layer of phospholipids
contains proteins that allow materials to pass through

Astudy was performed on 20 trees to test the effectiveness of a new fertilizer. the results of this specific study is brought into question. what would possibly improve the reliability of the results?

Adigestive system that is a series of tubes beginning at the mouth and ending at the anus is a digestive system.

In 2001, records showed that local stocks of fish were down worldwide. yet, records of harvests indicated that fish were being taken at records rates. what was actually happening?