Imagine that a researcher has discovered a 500 million-year-old leaf fossil from the Cambrian Period. He notices that the leaf had very few stomata compared to present-day leaves
What
does this tell the researcher about atmospheric CO2 levels during the Cambrian Period?
A. Atmospheric CO2 levels were higher
during the Cambrian Period compared to
today.
B. Atmospheric CO2 levels were lower during
the Cambrian Period compared to today.
C. Atmospheric CO2 levels during the
Cambrian Period were equal to present-day
levels.
D. Nothing, as CO2 was not part of Earth's
atmosphere during the Cambrian Period.
A
You might also like to view...
Consider the following two populations and the frequencies of alleles at the FGFR-1 locus. Allele 1 Allele 2 Allele 3 Allele 4 Population 1 0.25 0.25 0.25 0.25 Population 2 0.50 0.42 0.05 0.03 Which of the populations has greater allelic variation?
A. population 1 B. population 2 C. Neither; allelic diversity is the same for both populations.
What respiratory adaptation was important for the invasion of land by arthropods?
A. positive pressure breathing to increase gas exchange B. cutaneous respiration in moist habitats C. gas- and water-permeable exoskeletons D. the ability to close spiracles to prevent water loss E. countercurrent exchange surrounding the trachea
An embryo that is composed of a hollow ball of cells is called a blastocyst
a. True b. False
Maximum confidence is a procedure for reconstructing phylogenetic trees invoking the fewest number of steps or mutations
Indicate whether the statement is true or false