Q: The two complementary strands of what are separated, much like unzipping a zipper, in the initiation phase? Read this paragraph and choose the correct option from the provided answers: Stage 1: Initiation. The two complementary strands are separated, much like unzipping a zipper. Special enzymes, including helicase, untwist and separate the two strands of DNA. Stage 2: Elongation. Each strand becomes a template along which a new complementary strand is built. DNA polymerase brings in the correct bases to complement the template strand, synthesizing a new strand base by base. A DNA polymerase is an enzyme that adds free nucleotides to the end of a chain of DNA, making a new double strand. This growing strand continues to be built until it has fully complemented the template strand. Stage 3: Termination. Once the two original strands are bound to their own, finished, complementary strands, DNA replication is stopped and the two new identical DNA molecules are complete. Each new DNA molecule contains one strand from the original molecule and one newly synthesized strand. The term for this mode of replication is "semiconservative," because half of the original DNA molecule is conserved in each new DNA molecule. This process continues until the cell's entire genome, the entire complement of an organism's DNA, is replicated. As you might imagine, it is very important that DNA replication take place precisely so that new cells in the body contain the exact same genetic material as their parent cells. Mistakes made during DNA replication, such as the accidental addition of an inappropriate nucleotide, have the potential to render a gene dysfunctional or useless. Fortunately, there are mechanisms in place to minimize such mistakes. A DNA proofreading process enlists the help of special enzymes that scan the newly synthesized molecule for mistakes and corrects them. Once the process of DNA replication is complete, the cell is ready to divide. You will explore the process of cell division later in the chapter. Choices: - mRNA - Chromosomes - RNA - dna A:
dna

(Question)
Q: The main organs of the cardiovascular system are the blood vessels and what else? Read this paragraph and choose the correct option from the provided answers: The main organs of the cardiovascular system are the heart and blood vessels. Both organs contain valves. Valves also are found in plumbing systems. They can be turned on or off to control the flow of water. Choices: - alveoli - capillaries - lung - heart A:
(Answer)
heart

Ques: Q: What is another environmental benefit of conserving resources? Read this paragraph and choose the correct option from the provided answers: When we conserve resources, we also cut down on the trash we produce. Americans throw out 340 million tons of trash each year. We throw out 2.5 million plastic bottles aloneevery hour! Most of what we throw out ends up in landfills ( Figure below ). In a landfill, all those plastic bottles take hundreds of years to break down. What are the problems caused by producing so much trash? Natural resources must be used to produce the materials. Land must be given over to dump the materials. If the materials are toxic, they may cause pollution. Choices: - more jobs - warmer temperatures - lower prices - less trash A:
Ans: less trash

(Q).
Q: What is the process in which a solid changes directly to a gas called? Read this paragraph and choose the correct option from the provided answers: The process in which a solid changes directly to a gas is called sublimation . It occurs when the particles of a solid absorb enough energy to completely overcome the force of attraction between them. Dry ice (solid carbon dioxide, CO 2 ) is an example of a solid that undergoes sublimation. Figure below shows a chunk of dry ice changing directly to carbon dioxide gas. Sometimes snow undergoes sublimation as well. This is most likely to occur on sunny winter days when the air is very dry. What gas does snow become?. Choices: - condensation - solidification - vaporization - sublimation A:
(A).
sublimation

Ques:Q: What is used to classify tornadoes? Read this paragraph and choose the correct option from the provided answers: The winds of a tornado can reach very high speeds. The faster the winds blow, the greater the damage they cause. Wind speed and damage are used to classify tornadoes. Table below shows how. Choices: - seismograph - damage, snowfall - humidity, rain - wind speed, damage A:

Ans:wind speed, damage

Q: Reproduction that doesn't involve a male gamete is also known as what? Read this paragraph and choose the correct option from the provided answers: Agamogenesis is any form of reproduction that does not involve a male gamete. These include are parthenogenesis and apomixis. Parthenogenesis is a form of asexual reproduction where growth and development of embryos occur without fertilization. Parthenogenesis occurs naturally in aphids, rotifers, nematodes and some other invertebrates, as well as in many plants and certain lizards, such as the Komodo dragon. Apomixis is asexual reproduction, without fertilization, in plants. Choices: - meiosis - mitosis - asexual reproduction - agamogenesis A:
agamogenesis