In mollusks, ctenidia are necessary for which function?

a. breathing
b. excretion
c. reproduction
d. locomotion


a. breathing

Biology & Microbiology

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What are some diseases associated with imprinting?

A. Angelman Syndrome B. LHON C. Alzheimer's Disease D. All of the answers are correct

Biology & Microbiology

Proteinacious projections from the surface of a bacterium that are used to mediate conjugation are called sex ________, whereas projections that mediate attachment to surfaces such as host cells are called ________.

Fill in the blank(s) with the appropriate word(s).

Biology & Microbiology

Why is the protein-first hypothesis not accepted by most scientists?

a. Proteins cannot be catalysts. b. There is no known mechanism of protein self-replication. c. Of all of the macromolecules, only DNA can self-replicate. d. There is no evidence that proteins can store information. e. Proteins are too complex to have been the first "polymers of life."

Biology & Microbiology

The octameric histone core is composed of four different histone proteins, assembled in a stepwise manner. Once the core octamer has been formed, DNA wraps around it to form a nucleosome core particle

Which of the following histone proteins does not form part of the octameric core? (a) H4 (b) H2A (c) H3 (d) H1

Biology & Microbiology