( ( ( The ( Chicxulub ( impact crater ) ) ) ( in ( ( the ( Yucatan peninsula ) ) ( of Mexico ) ) ) ) ( ( is ( ( ( ( a ( large ( impact crater ) ) ) ( apparently ( caused ( by ( a ( 10 ( kilometer-diameter asteroid ) ) ) ) ) ) ) , ) ( ( the ( impact area ) ) ( extending ( ( ( ( at least ) 100 ) kilometers ) ( from ( the ( impact center ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NNP Chicxulub) (NN impact) (NN crater)) (PP (IN in) (NP (NP (DT the) (JJ Yucatan) (NN peninsula)) (PP (IN of) (NP (NNP Mexico)))))) (VP (VBZ is) (NP (NP (NP (DT a) (JJ large) (NN impact) (NN crater)) (VP (ADVP (RB apparently)) (VBN caused) (PP (IN by) (NP (DT a) (CD 10) (JJ kilometer-diameter) (NN asteroid))))) (, ,) (NP (NP (DT the) (NN impact) (NN area)) (VP (VBG extending) (NP (NP (QP (IN at) (JJS least) (CD 100)) (NNS kilometers)) (PP (IN from) (NP (DT the) (NN impact) (NN center)))))))) (. .)))
The Chicxulub impact crater in the Yucatan peninsula of Mexico is a large impact crater apparently caused by a 10 kilometer-diameter asteroid, the impact area extending at least 100 kilometers from the impact center.
(ROOT (S (NP (DT The) (NN lunar) (NN landscape)) (VP (VBZ is) (VP (VBN covered) (PP (IN by) (NP (NP (NNS craters)) (VP (VBN caused) (PP (IN by) (NP (JJ asteroid) (NNS impacts)))))))) (. .)))