Question

multiple choice 10 points
an epithelial membrane comes from
endoderm
ectoderm
mesoderm
any of the above
24 multiple choice 10 points
what is the earliest fossil evidence for life on earth?
stromatolites
burrows in sediment from burrowing organisms
the rise in sedimentary oxygen indicative of oxygenic photosynthesis
track on land from the first terrestrial animals
25 multiple choice 10 points
the evolution and spread of grasses on earth has been associated with what?

Explanation:

Question (about epithelial membrane origin):

Epithelial membranes can originate from different germ layers. Endoderm forms internal epithelial linings (e.g., digestive tract), ectoderm forms external epithelia (e.g., skin), and mesoderm forms some epithelial - like structures (e.g., lining of body cavities). So epithelial membranes can come from any of the three germ layers.

Stromatolites are layered structures formed by cyanobacteria (or similar early photosynthetic organisms) and are among the earliest fossil evidence of life on Earth. Burrows from burrowing organisms, sedimentary oxygen rise (a chemical signal, not a fossil), and tracks from terrestrial animals are all from later time periods compared to stromatolites.

Answer:

D. Any of the above

Question 24 (earliest fossil evidence for life on Earth):