Which of the following best describes the effects that fetal alcohol syndrome has on a child's mental abilities? a. fetal alcohol syndrome can cause parts of the brain to shut down, leading to a learning disability. b. fetal exposure to alcohol can damage a child's central nervous system, making it physically painful for them to learn fine motor skills. c. fetal alcohol syndrome can cause parts of the brain to be underdeveloped and can cause mental retrdation. d. fetal exposure to alcohol is the cause of numerous mental abnormalities, such as a smaller cerebrum.

Lyme disease is caused by a bacterium transmitted to people by deer ticks. deer ticks are almost never born infected with the bacterium, but they can pick it up from feeding on an infected host in any of the tick's three successive stage of development: larva, nymph, adult. once infected, a tick remains infected through any subsequent developmental stages, but since a tick feeds on only one host in each stage, it follows that . people can be infected only by being bitten by a tick that is either in larval stage or in the nymph stage b. people cannot be infected by a tick that picked up the lyme disease bacterium in the adult stage c. it is not possible for a person to be infected by a tick that is in the nymph stage or by a tick that was infected with the bacterium while in the nymph stage d. people infected with the lyme disease bacterium cannot transmit bacterium to adult deer ticks e. only deer ticks that are adults can transmit the lyme disease bacterium to people