Recent fossil discoveries may represent the earliest animal species ever found. How old are they?

a. 430 million years old
b. 25 million years old
c. 650 million years old
d. 5 billion years old


c. 650 million years old

Biology & Microbiology

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The portion of the electromagnetic spectrum between the 21-cm line of neutral hydrogen and the 18-cm line of OH is known as the ____________

Fill in the blank(s) with correct word

Biology & Microbiology

A Barr body exists for the purpose of

a. protein dosage compensation. b. insuring fertilization. c. blocking the activity of the Y chromosome. d. turning on the SRY gene. e. activating master genes

Biology & Microbiology

When the blood level of calcium falls below normal, which hormone stimulates osteoclasts to break

down bone and release calcium? a. growth hormone b. thyroid hormone c. calcitonin d. thyroid hormone e. PTH

Biology & Microbiology

For photosynthesis in green plants, the electron donor for the light dependent reaction is

A. RuBP. B. chlorophyll II. C. oxygen. D. water. E. carbon dioxide.

Biology & Microbiology