At one time, it was believed that thewas in the center of our Solar System. The and orbited around the . This theory was known at thetheory. The theory stated that the Solar System was centered. It was many years later that another theory was developed and it stated that the was in the center of our Solar System. The and the orbited around the . This theory stated that our Solar system is centered.

Fill in the blank 1. digestion occurs in the small intestine through the action of enzymes. 2. urea, excess water, and other waste materials are eliminated in a water fluid called 3. can cause infections by injecting dna or rna into hosts. 4. the human immune system produces in response to a vaccine, which later can bind to and destroy a pathogen if it invades. 5. are structures that link bone to bone at a joint 6. in the heart, blood flows from the right atrium to the right ventricle, where it is pumped to the the words i can use are: lymphocytes gliding pivot gas urine absorption dermis fulcrum lungs chemical viruses capillary vertebrae esophagus tendons antibodies synapses ligaments kidneys pathogens