In 1953, the scientists james watson and francis crick published their landmark findings on the structure of dna. watson and crick deduced the structure of dna by unifying evidence that they collected from several scientists who were also seeking to answer this important question.

identify the pieces of evidence describing the features of dna that watson and crick used to determine the structure of dna.

(a) purine base forms covalent bonds with a pyrimidine base located on the opposite dna helix.
(b) dna forms a right-handed double helical structure with two polynucleotide chains coiled around a central axis.
(c) the two chains are parallel, both running in a 5' to 3' direction.
(d) a purine base forms hydrogen bonds to pair with a pyrimidine base located on the opposite dna strand. specifically, a pairs with t, and c pairs with g.
(e) the sugar-phosphate backbones of each dna helix run antiparallel to one another.
(f) the diameter of the dna double helix is 2 nanometers, with each purine-pyrimidine base pair spanning an equivalent distance between the two chains.

The correct selection of answers to the question: Identify the pieces of evidence describing the features of DNA that Watson and Crick used to determine the structure of DNA, would be:

C: The two chains are parallel, both running in a 5´ to 3´ direction

D: A purine base forms hydrogen bonds to pair with a pyrimidine base located on the opposite DNA strand. Specifically, A pairs with T, and C pairs with G.

E: The sugar-phosphate backbones of each DNA helix run antiparallel to one another

F: The diameter of the DNA doube helix is 2 nm, with each purine-pyrimidine base pair spanning an equivalent distance between the two chains.

Explanation:

Although Watson´s and Crick´s research, and model of the DNA helix, became the breakthrough for science, as it visually presented the now known characteristics of DNA, this research was possible due to the way that these two researchers used previous information found by other scientist on the molecule, to finally build their model. All of the options that were selected were part of the research of several scientis, including Mendel, Rosalin Franklin, Linus Pauling, Maurice Wilkins, Oswald Avery and many others, who worked on different aspects of specimens and their specific characteristics, and which led them to discover that organisms possessed DNA, that this was the unit of information that directed all functions in living cells and how this DNA helix was chemically built to understand how it worked, and why it worked the way it did.

the answer to your question is b

answer: decrease

a limiting factor is the one which decrease the abundance, distribution and causes extinction of the population of species in a ecosystem. here, predators including hawks, owls and snakes are the limiting factor for the population of mexican free tailed bat.   although bats are nocturnal animals as they forge for food at night these predators also may remain active during night which can decrease the population of the mexican free-tailed bats. also, these bats eat only one type of insects that are moths. the food can also be a limiting factor as all 400 members are dependent upon same type of food needs that are moths. the decrease in the moth population can cause decrease in population size of the mexican free-tailed bats.

therefore, the scenarios will most likely to decrease the population size of the mexican free-tailed bats.