Stuck on number 4 down16 down 3 across

What is a cordon and where is it found

Iwill make you brainliest pleeze answer this fast i have to turn it in really soon brainliest promise easy question 6th grade ! a weather map shows a high pressure system with circles around it. what does this mean? a) an occluded front b) areas of equal altitude c) areas of equal pressure d) a stationary front

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.