Which situation will most likely cause the sustainability of an ecosystem to weaken?

A zebra is killed and eaten by a lion.
A disease wipes out several plant species.
A frog lays hundreds of eggs that hatch into tadpoles.
A dry season causes a few small trees to die.

The balanced chemical equation for this lab is: 3cucl2(aq) + 2al(s) 3cu(s) + 2alcl3(aq) if 10.5 g copper chloride react with 12.4 g aluminum, what is the limiting reactant?

__can be defined as which velocity changes

In a heat engine of 1000 j of heat enters the system and the piston does 500 j of work what is the final internal energy of the system if the inital energy was 2000 j we have to do all of these down here 1)write the equation 2)list out your know variables 3)plug the numbers into the equations 4)solve 5)write your solution statemtn that includes inital energuy and final energuy added