Planets of the solar system

What are some possible short and long term medical concerns for crew members on longer space exploration trips

Match the reproductive structures based on their function and the system to which they belong. egg ovary sperm vas deferens vagina fallopian tube testis urethra

Which of the following statements is true about the relationship between genetic variation and natural selection? a. genetic variation must be present in a population before natural selection can act on it. b. genetic variation arises in a population as a result of natural selection. c. natural selection can act on a population whether there is genetic variation within the population or not. d. after natural selection acts on a population, the amount of genetic variation in the population always increases.