if a second stimulus arrives before the relaxation phase has ended, a second, more powerful contraction occurs. this addition of one twitch to another is called

Match the deficiencies with their proper definitions: 1. deficiency disease 2. niacin (b3) deficiency 3.vitamin a deficiency 4.vitamin b1 deficiency 5.vitamin d deficiency 6.vitamin c deficiency a. abnormal conditions due to the absence of specific substances usually found in a normal diet b. susceptible to infection, partial or complete blindness, unhealthy skin c. fatigue, depression, irritability, low blood pressure, loss of appetite d. inflammation of the mouth, sores around the mouth, red and thickened skin, diarrhea, vomiting, etc e. weakness, bleeding into tissues, excessive bruising, softening of bones f. bones not normally hardened and become bent or twisted (answer format ex. 1 - a, 2 - b, 3 - c, etc.) will award brainliest

The outermost layer of your teeth is called the enamel and is made of?

Which description best defines the nervous system and its two main branches? a: the message center of the body, split into the autonomic nervous system and the somatic nervous system b: the control panel of the body, split into the central nervous system and the exterior nervous system c: the message center of the body, split into the central nervous system and the peripheral nervous system d: the control panel of the body, split into the brain and the spinal cord