The distance between earth and its moon is 384000000 meters. express this distance in kilometers.

384000000m

to change from m to km you just need to divide that give unit in Meters by 1000

which equals,
384000

so,

384000000 meters = 384000 kilometers

Are you going to give an example of the plant or?

The population of unionid mussels decreased after zebra mussels were introduced. zebra mussels competed with the unionid mussels for food. the zebra mussels were able to displace the unionid mussels, allowing the zebra mussel population to increase  over the years. the unionid mussel population decreased because  of lack of food.