Which of the following statements is true?
a. the first vaccine was developed for cowpox.
b. before jenner's vaccine, there was no prevention for smallpox.
c. travelers to other countries are often required to get special vaccinations. d. missed immunizations cannot be given at future doctor visits.

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

Jordan is now 19-years old. as an infant, jordan reached many gross motor skill milestones, such as holding his head up, rolling over, sitting, and standing, at normal times. however, he was considered a "late walker" because he took his first steps at 17 months. by 2 years old, his parents noticed a hyperlordotic posture while he was standing. a gower's sign and trendelenberg gait were noted by age four. throughout his childhood, he suffered progressive muscle weakness, especially in the proximal musculature of the arms, pelvis, and legs. he required orthotic braces to assist his walking and was confined to wheelchair ambulation by age 13. at 16, he was hospitalized with bronchitis requiring antibiotic treatment, but recovered. jordan has a history of progressive muscle weakness, but no history of muscle pain or spasm, chest pain, or irregular heartbeat. the only medications that he normally takes are calcium and fluoride supplements. jordan has three siblings. his older and younger sisters have never had any major medical issues. jordan's older brother is also to a wheelchair with problems similar to jordan's. no other immediate or distant family members have musculoskeletal issues.1. jordan’s history aligns most closely with which diagnosis? a. amyotrophic lateral sclerosisb. multiple sclerosisc. duchenne muscular dystrophyd. myotonic dystrophy2. jordan had a biopsy of the left gastrocnemius muscle when he was 5 years old. based on your answer for his diagnosis, describe the microscopic pathological changes that the pathologist would have noted.3. explain, in your own words, why jordan’s brother appears to have the same disease and why his sisters are unaffected.

True or false mucous membranes destroy pathogens on the outer body surface, at body openings.