scientists compare the dna of different organisms to understand evolutionary relationships what is this type of evidence called

ATI TEAS 7

TEAS 7 science practice

1. Scientists compare the DNA of different organisms to understand evolutionary relationships. What is this type of evidence called?

A. Morphological evidence (comparing body structures)
B. Biochemical evidence (comparing molecules like proteins)
C. Geographic distribution evidence (where organisms live)
D. Genetic evidence (comparing DNA sequences)

Correct answer: D

Rationale: A) Morphological evidence involves comparing body structures of organisms, which can provide information about evolutionary relationships based on physical similarities and differences. However, DNA comparison is a more direct and accurate method for understanding evolutionary relationships. B) Biochemical evidence involves comparing molecules like proteins, which can also provide insights into evolutionary relationships. However, DNA comparison is considered more reliable due to the direct relationship between DNA sequences and genetic information. C) Geographic distribution evidence refers to where organisms live and how their distribution may provide clues about evolutionary history. While this can be informative, it is not as direct or specific as comparing DNA sequences. D) Genetic evidence involves comparing DNA sequences of different organisms to understand their evolutionary relationships. DNA comparison is a powerful tool in evolutionary biology because it provides direct information about genetic similarities and differences, offering precise insights into evolutionary relationships.

2. What is 0.875 converted to a fraction?

A. 7/8
B. 8/7
C. 3/4
D. 9/10

Correct answer: A

Rationale: To convert 0.875 to a fraction, we write it as 875/1000. Simplifying by dividing both the numerator and denominator by 125, we get 7/8. Therefore, the correct answer is A. Choice B (8/7) is incorrect as it represents a fraction greater than 1. Choice C (3/4) and Choice D (9/10) do not match the correct conversion of 0.875.

3. Which of the following correctly identifies a difference between the primary and secondary immune response?

A. In the secondary response, macrophages migrate to the lymph nodes to present the foreign microorganism to helper T lymphocytes.
B. The humoral immunity that characterizes the primary response is coordinated by B lymphocytes.
C. The primary response is quicker and more powerful than the secondary response.
D. Suppressor T cells are activated in the secondary response to prevent an overactive immune response.

Correct answer: C

Rationale: The correct answer is C. The primary immune response is slower and less powerful compared to the secondary immune response. During the primary response, immune cells encounter the antigen for the first time, necessitating the activation and proliferation of specific immune cells. In contrast, the secondary response benefits from memory cells that quickly recognize the antigen, enabling a faster and more potent immune response. Choices A, B, and D are incorrect. While macrophages play a role in presenting antigens to T cells, this is not a defining difference between primary and secondary responses. Humoral immunity involves B lymphocytes in both primary and secondary responses, so it does not differentiate the two. Suppressor T cells primarily function to regulate the immune response but are not a key factor distinguishing primary from secondary responses.

4. In a study evaluating which type of road salt deices a road most quickly, what is the independent variable?

A. Deicing time period
B. Road used for deicing
C. Type of road salt used
D. Amount of road salt used

Correct answer: C

Rationale: The correct answer is C, 'Type of road salt used.' In an experiment, the independent variable is the one manipulated by the researcher to observe its impact on the dependent variable. In this study, the researchers are altering the type of road salt used to determine its influence on the deicing speed, thus making it the independent variable. The other choices are not the independent variable as they are not deliberately manipulated in the experiment: A - 'Deicing time period' is an outcome measure dependent on the type of salt used; B - 'Road used for deicing' is not controlled or manipulated; D - 'Amount of road salt used' would be a potential confounding variable rather than the independent variable as it could affect the outcome along with the type of salt.

5. What is the temperature of 35°C in Kelvin?

A. 220
B. 238
C. 308
D. 345

Correct answer: C

Rationale: To convert Celsius to Kelvin, add 273.15 to the Celsius temperature. In this case, 35°C + 273.15 = 308.15 K. Therefore, the correct answer is 308 K. Choice A (220) is incorrect as it does not account for adding 273.15 to convert to Kelvin. Choice B (238) is incorrect as it is not the result of adding 273.15 to 35°C. Choice D (345) is incorrect as it is not the correct conversion of 35°C to Kelvin.