A Fourier analysis is a technique that is able to determine both the amplitude spectrum and the phase <span>spectrum of any signal</span>. This analysis is based on the finding that all sound waves can be derived by adding sinusoids together (so long as the sinusoids are of the appropriate frequencies, amplitudes, and phases).
Answer:
Molecular genetic approaches to the study of plant metabolism can be traced back to the isolation of the first cDNA encoding a plant enzyme (Bedbrook et al., 1980), the use of the Agrobacterium Ti plasmid to introduce foreign DNA into plant cells (Hernalsteens et al., 1980) and the establishment of routine plant transformation systems (Bevan, 1984; Horsch et al., 1985). It became possible to express foreign genes in plants and potentially to overexpress plant genes using cDNAs linked to strong promoters, with the aim of modifying metabolism. However, the discovery of the antisense phenomenon of plant gene silencing (van der Krol et al., 1988; Smith et al., 1988), and subsequently co‐suppression (Napoli et al., 1990; van der Krol et al., 1990), provided the most powerful and widely‐used methods for investigating the roles of specific enzymes in metabolism and plant growth. The antisense or co‐supression of gene expression, collectively known as post‐transcriptional gene silencing (PTGS), has been particularly versatile and powerful in studies of plant metabolism. With such molecular tools in place, plant metabolism became accessible to investigation and manipulation through genetic modification and dramatic progress was made in subsequent years (Stitt and Sonnewald, 1995; Herbers and Sonnewald, 1996), particularly in studies of solanaceous species (Frommer and Sonnewald, 1995).
C. often because t<span>here are three major types of </span>plate<span> boundaries. If </span>two<span> tectonic </span>plates<span> collide, they form a convergent </span>plate<span> boundary. Usually, one of the converging </span>plates<span> will move beneath the other, which is known as subduction. Deep trenches are often formed where tectonic </span>plates<span> are being subducted and earthquakes are common</span>
