Which process must occur for a muscle to be able to relax? ОА. .
The amount of ATP in the neuromuscular junction must increase.
OB. Myosin and actin must attach to each other.
OC.
A nerve must initiate an action potential in the muscle fiber.
OD
The concentration of calcium in the myofibril must decrease.

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