1. What has been suggested by research on fraternal and identical twinsa. More than half of the variation in memory scores may be accounted for bydifferences in genetic makeup2. Which statement is truea. Of those who survive beyond age 40, nearly all individuals with Down syndromedevelop amyloid plaques and neurofibrillary tangles3. Regarding learning a second languagea. you will be able to approximate native accents more closely if you learn as a childthan as an adult4. Which statement is true regarding neurogenesisa. The vast majority of newly born neurons in adults appear to die off within a fewweeks after formation5. Which statement is true regarding gender differences in learning and memorya. Females are better than males at remembering the positions of landmarks on a map,but this advantage does not emerge until puberty6. In humansa. up to 42% of all synapses in the cortex may be pruned during adolescence andadulthood7. In studies of emotion and episodic memory, elderly adults typically remembera. more positive than negative images8. Research has demonstrated that humansa. can demonstrate learning of basic sounds and language before they are born9. When Tryon (1940) bred "maze-bright" rats together, he found thata. with each generation, the rats' offspring made fewer errors10. The formation of an attachment to the first individual an organism sees after birthis known asa. Imprinting11. Some of the most dramatic changes in the adolescent brain occur in thea. prefrontal cortex12. With which memory task would elderly individuals have the MOST difficultya. a paired-associate learning test13. Which statement supports the idea that age-related improvement in workingmemory capacity at least partially reflects exposure to and familiarity with thematerial to be remembereda. Ten-year-old chess experts can remember more pieces than adults who do not playchess, even though the children's digit spans are lower14. By age 80a. human brains have lost about 5% of their weight15. Which type of memory ability is usually the first to show signs of impairment inpeople with Alzheimer's diseasea.