Answer the following question given this paragraph: DNA consists of two long chains of nucleotides. Nitrogen bases on the two chains form hydrogen bonds with each other. Adenine always bonds with thymine, and guanine always bonds with cytosine. These bonds hold the two chains together and give DNA is characteristic double helix, or spiral, shape. You can see the shape of the DNA molecule in Figure below . Sugars and phosphate groups form the "backbone" of each chain of DNA. The bonded bases are called base pairs. RNA, in contrast to DNA, consists of just one chain of nucleotides. Determining the structure of DNA was a big scientific breakthrough. You can read the interesting story of its discovery at the URL below. Q: Dna consists of how many long chains of nucleotides? Choices: - three - zero - one - two A:
two
Answer the following question given this paragraph: Fossils provide a window into the past. They are evidence for evolution. Q: Fossils provide a window into the past. they are evidence for what? Choices: - emergence - intelligent design - generation - evolution A:
evolution
Q: Answer the following question given this paragraph: The Levels of Organization To study the chemical level of organization, scientists consider the simplest building blocks of matter: subatomic particles, atoms and molecules. All matter in the universe is composed of one or more unique pure substances called elements, familiar examples of which are hydrogen, oxygen, carbon, nitrogen, calcium, and iron. The smallest unit of any of these pure substances (elements) is an atom. Atoms are made up of subatomic particles such as the proton, electron and neutron. Two or more atoms combine to form a molecule, such as the water molecules, proteins, and sugars found in living things. Molecules are the chemical building blocks of all body structures. Q: All matter in the universe is composed of one or more unique pure substances called what? Choices: - atoms - molecules - compounds - elements A:
A: elements
Question: Answer the following question given this paragraph: Fossils are a window into the past. They provide clear evidence that evolution has occurred. Scientists who find and study fossils are called paleontologists . How do they use fossils to understand the past? Consider the example of the horse, shown in Figure below . The fossil record shows how the horse evolved. Q: Scientists who find and study fossils are called what? Choices: - biologists - geologists - anthropologist - paleontologists A:
Answer: paleontologists
*Question*
Answer the following question given this paragraph: Mutation Mutations are changes to an organism's DNA and are an important driver of diversity in populations. Species evolve because of the accumulation of mutations that occur over time. The appearance of new mutations is the most common way to introduce novel genotypic and phenotypic variance. Some mutations are unfavorable or harmful and are quickly eliminated from the population by natural selection. Others are beneficial and will spread through the population. Whether or not a mutation is beneficial or harmful is determined by whether it helps an organism survive to sexual maturity and reproduce. Some mutations do not do anything and can linger, unaffected by natural selection, in the genome. Some can have a dramatic effect on a gene and the resulting phenotype. Q: What term is used to describe changes to an organism's dna and are an important driver of diversity in populations? Choices: - adaptations - pathogens - evolutions - mutations A:
**Answer**
mutations
Answer the following question given this paragraph: The general trend in electronegativity is that the value increases from left to right across a row in the periodic table and decreases down a column. The most electronegative element is fluorine, which has a value of 4.0. As discussed in the lesson "Trends in the Periodic Table," electronegativity increases across a row as the number of protons in the nucleus increases and therefore has a stronger pull. Electronegativity decreases down a column due to an increased effect of electron shielding in larger atoms. Q: Generally speaking, electronegativity values ______ from left to right across a row in the periodic table and _______ down a column. Choices: - reverse, descend - move, fall - decrease, increase - increase, decrease A:
increase, decrease