Approximately how old is life on Earth?

A) 36 billion years old
B) 3.6 billion years old
C) 360 million years old
D) 36 million years old


B

Biology & Microbiology

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__________occurs when two species act as agents of

selection upon one another. Fill in the blank(s) with the appropriate word(s).

Biology & Microbiology

The type of anemia that results from a deficiency of vitamin B12 is ________; the type of anemia that results from extreme blood loss is ________

Fill in the blank(s) with correct word

Biology & Microbiology

Which one of the following is characteristic of T lymphocytes but NOT B lymphocytes?

A) direct attack of antigen-bearing cells B) production of immunoglobulins C) maturation in the red bone marrow D) production of plasma cells E) antibody-mediated immunity

Biology & Microbiology

What type of connection exists between the atoms at the point labeled 1 in the accompanying figure?

a. peptide bond b. disulfide bond c. hydrogen bond

d. glycoside linkage e. phosphodiester linkage

Biology & Microbiology