Simple diffusion
A. moves molecules against a concentration gradient.
B. cannot occur without a membrane present.
C. requires energy.
D. utilizes proteins to move molecules across a membrane.
E. does not require energy.
E. does not require energy.
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Inbred lines of animals, such as laboratory mice, are useful for studying complex traits because:
A. individuals are genetically identical, so differences in traits must be due to environmental differences. B. although individuals differ both genetically and environmentally, the genetic differences are known, so differences in traits can be understood. C. animals are kept in identical environments, so any differences in traits are due to differences in their genes. D. both genetic and environmental differences between individuals are known, making differences in their traits easy to understand. E. None of these choices is correct.
Answer the following statements true (T) or false (F)
1. All materials passing from one hyphal cell to another must diffuse across the septal wall. 2. Conidia are sexual spores produced by mushrooms. 3. Lichens are monophyletic. 4. Many kinds of ascomycetes and basidiomycetes have lost the ability to reproduce sexually.
Which phyllotaxes allow for leaves on a stem to lie flat without bending or breaking?
a. spiral and opposite b. alternate and whorled c. alternate and opposite d. spiral and whorled
When a gene is carried on one of the sex chromosomes, it is said to be ________.
Fill in the blank(s) with the appropriate word(s).