The exact path that led to the evolution of modern cells and the organic molecules contained in these cells to support life is not known
The best guess is that some sort of self-replicating organic molecule formed along mudflats and most likely resembled A) single-stranded DNA.
B) single-stranded RNA.
C) small amino acids such as lysine and glycine.
D) double-stranded DNA.
E) ATP.
B
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The units of genetic distance derived from bacterial conjugation studies are called _____
A. seconds B. map units C. centimorgans D. recombination units E. minutes
The geologic time scale is often subdivided on the basis of ____
a. the appearance of different radioactive isotopes in different strata b. levels of background extinction c. periods of mass extinction d. the appearance of new species e. climate change
Which of the following statements is false?
a. Ovulation occurs when the follicle ruptures and releases an egg. b. The zygote divides by mitosis during cleavage. c. Fertilization occurs in the upper regions of the oviduct. d. The blastocyst implants in the endometrial lining of the uterus. e. Implantation occurs about 36 hours after fertilization.
Which type of DNA makes up the smallest portion of the human genome?
A) introns B) unique noncoding DNA C) exons D) tandemly repeated DNA E) interspersed repeated DNA