What event marks the end of both the paleozoic era and mesozoic era?

a. the ice age

b. the appearance of birds

c. a mass extinction of plants and animals

d. the breakup of a supercontinent

Answerscripps institution of oceanography; i believe this is correct plz check first good luck;

Answer (d) the greenhouse effect is primarily caused by car and trucks;

The us is first  the  u.s. economy  remains the  largest in the world  in terms of nominal  gdp. however, the  u.s. economy  loses its spot as the number one  economy  to china when  measured  in terms of  gdp  based on ppp. in these terms, china's  gdp  is $23.19 trillion exceeds the  u.s. gdp  of $19.42 trillion