Помощь в АНГЛИЙСКОМ ЯЗЫКЕ (глагол-сказуемое)

Question

Помогите найти глагол-сказуемое и определить его видовременную форму и залог 
1. The US Environmental Protection Agency (EPA) was established in December 1970, bringing together in a single agency the many federal programs to protect environment. 
2. The biosphere is strongly affected by all sorts of human activity. 
3. The problem has already been discussed at a large number of conferences. 
4. Scientists are studying various aspects of human biology and the origin and development of human race.

Владислав · Accepted Answer

1. was established - Past Simple Passive 2. is affected - Present Simple Passive 3. has been discussed - Present Perfect Passive 4. are studying - Present Progressive Active