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).
The human reproductive system is regulated by the endocrine system.
The correct answer is "coarctation of the aorta". In coarctation of the aorta, there is an abnormal narrowing of the aorta, most commonly in the abdominal aorta, which compromises blood flow from going into the lower extremities. Patients with coarctation of the aorta most commonly presents with tachypnea as this is a high pressure congenital heart defect which makes breathing harder for the baby; diminished femoral pulses and poor lower body perfusion as the narrowing compromises blood flow. In physical examination, there will be a narrow ankle-brachial index, or the difference between the pulse pressures of the ankle (lower extremity) and the brachium (upper extremity).
Answer:
The correct answer is - Fossil fuels are cheaper than alternative forms of energy.
Explanation:
Fossil fuels are made by the natural process in a longer time period such as anaerobic decomposition of the dead organism like plants, and animals. These plants and animal's decomposed organic matter pilled up to form coal, or natural gases or crude oil.
By the use of such fuels the reserves are continuously depleting and will be no longer available in the future if not managed properly as it can not be renewed. Fossil fuels increases the green house gases in environment and affect it by incresing carbon in atmosphere. However, these fuels are cheaper in comparision of other fuels.
Thus, the correct answer is - Fossil fuels are cheaper than alternative forms of energy.
