Drugs are substances that produce physiological or psychological effects in humans. true false

Sydney drew a flow chart to illustrate the nitrogen cycle.which labels best complete the flow chart? x: producers undergo photosynthesis.y: nitrogen compounds are released into the air.x: nitrogen compounds are released into the air.y: producers undergo photosynthesis.x: free nitrogen is in the atmosphere.y: producers absorb nitrogen compounds through their roots.x: producers absorb nitrogen compounds through their roots.y: free nitrogen is in the atmosphere.

List two limitations of natural selection

The first generation of offspring from the cross of two parents is called the a.f1 generation b.f2 generation c.short generation d.p generation