If babies are consistently placed on their backs without any restrictions, what will happen to their development ?
A. they suffer from weakness in certain muscle groups
B. their ability to roll over , crawl, and eventually walk is hindered .
C. they suffer brain damage from the pressure on the back of the head
D. they learn to roll over , crawl, and eventually walk on their own .

Hiv is inactivated in the laboratory after a few minutes of sitting at room temperature, but the flu virus is still active after sitting for several hours. what are the practical consequences of these findings? a) hiv can be transmitted more easily from person to person than the flu virusb) the flu virus can be transmitted more easily from person to person than hivc) this property of hiv makes it more likely to be a pandemic than the flu virusd) disinfecting surfaces is more important to reduce the spread of hiv than the flu