Which epidermal cell produces the pigments that lead to the coloration of the skin?
a. Collagen fibers
b. Keratinocytes
c. Melanocytes
d. Stratified squamous epithelium
e. Elastin fibers
c
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Ions can be moved against the concentration gradient to create a difference in charge across that membrane. Later, the electrochemical gradient can be exploited by the cell to drive other processes. Respectively, what are these two mechanisms called?
a. primary passive transport, secondary passive transport b. primary sodium transport, secondary potassium transport c. primary active transport, secondary active transport d. primary electrical transport, secondary electrical transport
In mitosis,
a. the chromosome number is halved. b. the chromosome number is doubled. c. the chromosome number stays the same. d. the chromosome number may double or be halved depending on the species. e. gametes are formed in bacteria only
The land mass labeled 2 in Figure 18-2 is called:
a. Eurasia.
b. Laurasia.
c. Antarctica.
d. Gondwana.
e. Pangea.
What are the issues around the use of biofuels as an alternative to fossil fuels?
What will be an ideal response?