Fossils and Evidence of Past Life — Answer Key
Part A: Fix the Sentence
Each sentence has an error. Rewrite it correctly on the line.
1. Fix the sentence:
A trilobite were a sea creature with a hard shell in Grade 3 science books.
Corrected: A trilobite was a sea creature with a hard shell in Grade 3 science books.
The singular subject 'a trilobite' needs 'was', the singular past-tense form of 'be'.
2. Fix the sentence:
Dinosaur bones is often found inside sedimentary rock in Grade 3 science.
Corrected: Dinosaur bones are often found inside sedimentary rock in Grade 3 science.
Plural subject 'bones' takes the plural verb 'are' instead of the singular 'is'.
3. Fix the sentence:
Amber sometime traps insects that lived long ago in Grade 3 lessons.
Corrected: Amber sometimes traps insects that lived long ago in Grade 3 lessons.
'Sometimes' is the correct adverb form; 'sometime' means an unspecified future time.
Part B: Fill in the Blank
Write the missing word or number on each line.
1. In Grade 3 science, hardened tree sap that can trap ancient insects is called amber.
Amber is fossilized tree resin that preserves insects and plants in perfect detail.
2. In Grade 3 science, trilobites were ocean animals with segmented bodies and are now extinct.
Trilobites were ancient sea arthropods with three body lobes that vanished long ago.
3. In Grade 3 science, huge mammoth tusks have been found frozen in icy ground.
Mammoths were large, woolly relatives of elephants whose tusks are found in permafrost.
4. In Grade 3 science, black coal often contains fossil fern leaves from ancient forests.
Coal forms from buried plants and often preserves fern and leaf fossils from old swamps.
Part C: True or False?
Read each statement. Circle True or False.
1. In Grade 3 science, trilobites are still alive today in most oceans around the world.
True False
Trilobites are extinct and only survive as fossils in ancient sea rocks.
2. In Grade 3 science, insects trapped in amber can be preserved for millions of years.
True False
Amber seals insects from air and bacteria, preserving tiny details for millions of years.
3. In Grade 3 science, dinosaur bones are usually found inside smooth, shiny glass.
True False
Dinosaur bones appear in sedimentary rock layers, not in glass, which is man-made.