Cells of the immune system are able to respond
to the presence of invading organisms because
they recognize the
(1) antigens present on the invaders
(2) antibodies present in invading pathogens
(3) dna pattern in the nuclei of viruses
(4) antibiotics released from microbes

What happens when the cell copies its chromosomes

What causes the force that pushes magma from the magma chamber through the pipe and vent of a volcano?

Select the situation bellow that would produce a total displacement of zero. a. a trip to the moon and then to mars b. a horse galloping from one end of a field to another c. the criss-crossing path of a bug as it flies from flower to flower d. a round-trip ride to school and back