Histone modification: is fixed; once a histone is modified, it stays that way and the genes with which it is associated are turned on or off permanently. is random and independent of the environment or cell type. is fixed, but this has no effect on whether genes are expressed. can change over time in response to environmental cues, allowing genes to be turned on or off as needed. can change over time in response to environmental cues, but this has no effect on gene expression.

Match the type of adaptation to the correct example, structural adaptation functional adaptation behavioral adaptation example type of adaptation elephants live in herds to protect their young leaves of a rain forest plant species have a pointed tip that enables rainwater to drain off easily. camels have nostrils that they can close snakes produce venom to kill prey and defend themselves. earthworms coil when touched, as part of a defense mechanism. human skin darkens with increased exposure to sunlight.

The most effective way to provide children with safety messages is to

What’s a example of extrusive rock that cooled to quickly for grains to form