Adhesion proteins and ____ help guide the growth of the pollen tube in the proper direction towards the egg.
A. differentiation upon contact with the flower
B. exposure to moisture
C. species-specific signaling molecules
D. electromagnetic impulses from the flower
E. insertion of the pollen tube
Answer: C
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Algae in the genus Caulerpa typically grow to a length of over half a meter and have structures similar to stems, leaves, and roots. Reproduction occurs when adults produce sperm and eggs that fuse to form offspring. Algae in the genus Caulerpa typically grow to a length of over half a meter and have structures similar to stems, leaves, and roots. Reproduction occurs when adults produce sperm and
eggs that fuse to form offspring. Each adult Caulerpa consists of just a single cell, however. Which of the following statements is true? A) Caulerpa violate the pattern component of the cell theory that all organisms consist of cells. B) Caulerpa violate the process component of the cell theory that all cells come from preexisting cells. C) Caulerpa violate both the pattern and process components of the cell theory. D) The existence of Caulerpa is consistent with the cell theory.
Cooking oil and gasoline (a hydrocarbon) are not amphipathic molecules because they _____
A) do not have a polar or charged region B) do not have a nonpolar region C) have hydrophobic and hydrophilic regions D) are highly reduced molecules
Common alleles of genes other than BRCA1 ____
a. dictate the types of mutations that occur in BRCA2 b. cause uncontrolled division of the BRCA2 gene c. cause the interruption of the cell cycle in any cell containing a BRCA2 mutation d. have a strong influence on whether a carrier will develop breast cancer e. have very little influence on whether a carrier will develop breast cancer
The real goal of hypothesis testing is to
A) eliminate incorrect ideas. B) form a theory. C) fully explain observations. D) understand why science never changes.