When we use electronic devices in the classroom we must be: - We have to be careful and always inspect all electrical equipment before using, - Regularly inspect the equipment, - Keep the power cord away from the floor and do not place objects on it- - The ropes should not be twisted - Attention must be paid to the electrical device while it is being used.
Collar cells have a sticky funnel-shaped collar and a hair-like whip that is called the flagellum. A cell called an amebocyte takes the food picked up by a collar cell to other cells within the sponge. Collar cells are also called choanocytes
