The ________ of materials moved through the phloem occurs because of water pressure.
A. stoppage
B. inhibition
C. mass flow
D. growth
Answer: C
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Primary growth occurs at ____ and secondary growth occurs at ____
a. apical tissue; lateral tissue b. apical meristems; lateral meristems c. primary meristems; secondary meristems d. vascular cambium; cork cambium e. lateral cambium; apical cambium
Copyright© The Mc-Graw-Hill Companies,Inc, Permission Required for reproduction or display.Based on a variety of experiments, it is known that the rate of photosynthesis is highest when wavelengths of light between 400 and 500 nm are used, and when wavelengths around 700 nm are used. What does this indicate about the relative importance of chlorophyll a and b in photosynthesis?
A. Reflection of light by chlorophyll a and b is essential for the process of photosynthesis B. Absorption of light by chlorophyll a and b is essential for the process of photosynthesis C. Transmission of light by chlorophyll a and b is essential for the process of photosynthesis D. Chlorophyll a and b are much less important than other pigments in the reflection, absorption and transmission of light relevant to photosynthesis
Mendel postulated that individuals have genetic elements that exist in pairs, which determine a single phenotype. What do we now know these pairs of elements to be?
A) a sperm and an egg B) pairs of centromeres C) two alleles of a gene on homologous chromosomes D) two haploid sets of chromosomes E) pairs of sister chromatids
A DNA library has been constructed by purifying chromosomal DNA from mice, cutting the DNA with the restriction enzyme NotI, and inserting the fragments into the NotI site of a plasmid vector. What information cannot be retrieved from this library?
(a) gene regulatory sequences (b) intron sequences (c) sequences of the telomeres (the ends of the chromosomes) (d) amino acid sequences of proteins