homologous structures are similar structures in different organisms that have a common evolutionary origin an example is

ATI TEAS 7

TEAS Test 7 science

1. Homologous structures are similar structures in different organisms that have a common evolutionary origin. An example is:

A. Butterfly wings and bird wings (analogous structures with different origins)
B. The arm of a human, the wing of a bat, and the flipper of a whale
C. The eyes of an octopus and a human (convergent evolution with different origins)
D. The stinger of a bee and the barb of a cactus (unrelated structures)

Correct answer: B

Rationale: Homologous structures are similar structures found in different organisms that share a common evolutionary origin. The arm of a human, the wing of a bat, and the flipper of a whale are all examples of homologous structures. Despite serving different functions, they share a common underlying structure due to their evolutionary relationship, evidencing a shared ancestry. These structures are modified over time to suit the specific needs of each species. Option A (Butterfly wings and bird wings) refers to analogous structures with different origins. Option C (The eyes of an octopus and a human) describes convergent evolution where traits evolve independently. Option D (The stinger of a bee and the barb of a cactus) are unrelated structures.

2. Which of the following organs is responsible for producing bile?

A. Pancreas
B. Liver
C. Gallbladder
D. Stomach

Correct answer: B

Rationale: The correct answer is B: Liver. The liver is responsible for producing bile, which aids in fat digestion. The pancreas produces digestive enzymes, the gallbladder stores bile produced by the liver, and the stomach primarily secretes gastric acid for digestion. Therefore, choices A, C, and D are incorrect as they do not directly produce bile.

3. What property of a substance measures the amount of matter per unit volume?

A. Mass
B. Weight
C. Density
D. Volume

Correct answer: C

Rationale: Density is the property of a substance that measures the amount of matter per unit volume. It is calculated by dividing the mass of an object by its volume. Mass refers to the amount of matter in an object, weight is the force of gravity acting on an object, and volume is the amount of space an object occupies. Therefore, in this context, density is the correct answer as it specifically relates to the concentration of matter within a given volume.

4. Which of the following reagents can be used to convert a primary alcohol to an alkyl halide?

A. HI
B. H2O
C. NaOH
D. SOCl2

Correct answer: D

Rationale: SOCl2 (thionyl chloride) is commonly used to convert primary alcohols to alkyl halides through an SN2 mechanism. Thionyl chloride reacts with the alcohol to form an alkyl chloride. HI (hydroiodic acid) is typically used to convert alcohols to alkyl iodides specifically, not alkyl halides in general. H2O (water) and NaOH (sodium hydroxide) are not reagents used for converting alcohols to alkyl halides. Therefore, the correct answer is SOCl2 as it facilitates the conversion of primary alcohols to alkyl halides, unlike the other options provided.

5. How are genetic markers utilized in paternity testing?

A. They identify unique sequences in the father's DNA present in the child.
B. They analyze the presence or absence of specific alleles for certain genes.
C. They compare the child's blood type to the parents' blood types.
D. They measure the child's physical resemblance to the father.

Correct answer: B

Rationale: Genetic markers are specific DNA sequences that can vary among individuals. In paternity testing, genetic markers are used to compare the DNA of the child with that of the alleged father. By analyzing the presence or absence of specific alleles (different forms of a gene) at these genetic markers, scientists can determine the likelihood of paternity. This method is more accurate and reliable than comparing blood types (choice C) or physical resemblance (choice D) as genetic markers provide a direct comparison of DNA sequences between individuals. Therefore, option B is the correct choice as it accurately describes the use of genetic markers in paternity testing.