Some scientists predict that the Earth will lose almost all of its topsoil by the middle of the next century. What factors are involved in the erosion of soil?
A. poor farming practices
B. deforestation
C. desertization
D. All of these factors cause erosion.
Answer: D
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The rate of exchange of carbon between the atmosphere and the oceans represents a carbon:
A. sink. B. reservoir. C. biomass. D. precipitation. E. flux.
During endocytosis, if a bacterial cell is not degraded and bacterial DNA is taken up by the eukaryotic cell, what may have occurred?
A. vertical evolution. B. horizontal gene transfer. C. vertical exon shuffling. D. chromosomal duplication and genomic exchange. E. both chromosomal duplication and vertical evolution.
An enzyme is thought to optimize the fit between substrates by restraining and stretching or squeezing them into
certain shapes and moving them to the transition state, as described by the ____ model of enzyme activity.
a. lock and key b. induced-fit c. template d. activation e. conformational
The use of SNPs for analyzing genomes is
based on a. the nucleotide base pairing in the SNPs. b. the types of nucleotides in the SNPs. c. differences in SNPs among individuals. d. the ratio of purines to pyrimidines in SNPs. e. bonding patterns between nucleotides in the SNPs.