What is the function of an electromagnet in an electric doorbell? 1) it acts as a switch to open the circuit 2) it acts as a switch to close the circuit. 3) it repels a metal striker, which then pulls away from the bell 4) it attracts a metal striker, which then hits the bell.

4) it attracts a metal striker, which then hits the bell.

Explanation:

An electric doorbell uses an electromagnet. When the switch is pressed, the circuit gets complete which generates electric current in the wire. The wire is coiled around a metal. When current flows through the coiled wire, magnetic field is generated. This magnetic field attracts the striker which then hits the bell and sound is produced.

ysosomes are membrane-bound vesicles that contain digestive enzymes, such as glycosidases, proteases and sulfatases. lysosomal enzymes are synthesized in the endoplasmic reticulum (er), are transported to the golgi apparatus, and are tagged for lysosomes by the addition of mannose-6-phosphate label.

explanation:

i'd say that the moon rock is about 2.2 billion years old.