A major problem for land plants is water conservation. Most water is lost through stomata due to evaporation at the surface of the leaf. Many plants, including lilac (the leaf section you examined), orient their leaves perpendicular to the drying force of the sun’s rays. What did you observe about the relative abundance of stomata in the lower epidermis versus the upper epidermis? Why do you think this distribution has evolved?
What will be an ideal response?
More stomata are found on the lower leaf surface. The distribution subjects the stomata to less heat from the sun and hence fewer evaporative forces. Consequently, less water would be lost even though the stomata are open to allow carbon dioxide to enter the leaf for photosynthesis.
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A form of mutation associated with the expansion in copy number of a nucleotide triplet in or near a gene is called a(n) ____________________
Fill in the blank(s) with correct word
During contraction
a. cross bridges of muscle filaments are broken and reformed. b. ATP is released as a biproduct from cross-bridges. c. muscle cells use phosphate as their energy source. d. if there is an abundant supply of oxygen, glycogen depletion by glycolysis will lead to fatigue. e. calcium is linked to the myosin head.
Which of these was the dominant plant group at the time that dinosaurs were the dominant animals?
a) bryophytes b) charophyceans c) seedless vascular plants d) gymnosperms e) angiosperms
In the case of comparing birds to other vertebrates, having four appendages is
a. a shared ancestral character. b. a shared derived character. c. a character useful for distinguishing the birds from other vertebrates. d. an example of analogy rather than homology.