Which of the following shows natural selection? Select one: a. Pigs are bred to produce more meat. Mothers care for their young. b. Corn is planted every year. Large ears of corn are kept to plant the next crop. c. Sparrows tend to choose mates that eat similar sized seeds. Their offspring tend to also favor the same sized seeds as their parents.” d. A dog's parents were racers. The fastest dogs are bred to make the fastest puppies. PLZ HELP NOW

Scientists are conducting a study on the effectiveness of a new drug on memory loss. they are giving some of the test subjects the new drug to find out if it improves their long-term memory. which are possible limitations of this study? check all that apply. a) test subjects may want to participate in additional experiments. b) test subjects may think they should be paid more. c) test subjects may get bored and want to quit early. d) test subjects may have to travel during the experiment. e) test subjects may have full-time jobs. this is multiple choice. you for the !