the fossil record shows that dinosaurs with feathers existed millions of years before birds this is evidence for

ATI TEAS 7

ati teas 7 science

1. The fossil record shows that dinosaurs with feathers existed millions of years before birds. This is evidence for

A. Convergent evolution (unrelated organisms evolving similar traits)
B. Divergent evolution (related organisms evolving different traits)
C. Coevolution (two species influencing each other's evolution)
D. The extinction of dinosaurs due to an asteroid impact

Correct answer: A

Rationale: The fossil record indicates that dinosaurs had feathers before birds, suggesting convergent evolution. Convergent evolution occurs when unrelated organisms independently evolve similar traits to adapt to similar environmental pressures. In this case, both dinosaurs and birds developed feathers for flight or insulation purposes, even though they are not closely related. This evidence supports the concept of convergent evolution rather than divergent evolution, coevolution, or the extinction of dinosaurs due to an asteroid impact. Therefore, the correct answer is A, as it best explains the scenario where dinosaurs with feathers existed before birds, showcasing the concept of unrelated organisms evolving similar traits independently.

2. In order to verify if a particular drug is responsible for the recovery of individuals with a disorder, what procedure would be most effective in testing its effectiveness?

A. Ensure that neither the subjects nor the investigators know which subjects are given the drug and which are given the placebo.
B. Ensure that the subjects do not know whether they are given the drug or the placebo, but the investigators are aware of who has received the medication.
C. Ensure that the investigators do not know whether they are administering the drug or the placebo, but the subjects do know which they are receiving.
D. Ensure that both the investigators and the subjects have full knowledge of which subjects are getting the drug and which are getting a placebo.

Correct answer: A

Rationale: The most effective procedure in testing whether the drug is responsible for the recovery is to ensure that neither the subjects nor the investigators know which subjects are given the drug and which are given the placebo. This method is known as a double-blind study, which helps eliminate biases and ensures that the results are reliable and not influenced by expectations or beliefs. By keeping both the subjects and investigators unaware of who is receiving the drug or placebo, the study can accurately determine the true impact of the drug on recovery. Choice B is incorrect as it only prevents the subjects from knowing which treatment they are receiving, allowing for potential bias from the investigators. Choice C is also incorrect as it allows for potential bias from the subjects. Choice D is incorrect as full knowledge of treatment allocation can introduce bias and affect the study's validity.

3. Which of the following are functions of the urinary system?

A. I, II, and III
B. II and III
C. II, III, and IV
D. All of the above

Correct answer: D

Rationale: The corrected answer is D, 'All of the above.' The urinary system performs multiple essential functions to maintain the body's internal environment. Synthesizing calcitriol and secreting erythropoietin are crucial roles of the kidneys. Regulating the concentrations of sodium, potassium, chloride, calcium, and other ions helps in maintaining the electrolyte balance. Reabsorbing or secreting hydrogen ions and bicarbonate is vital for managing the body's acid-base balance. Furthermore, the urinary system is involved in detecting reductions in blood volume and pressure, aiding in the maintenance of blood pressure levels and fluid balance in the body.

4. Which type of blood cell is primarily responsible for fighting infections?

A. Red blood cell
B. White blood cell
C. Platelet
D. Plasma

Correct answer: B

Rationale: The correct answer is B: White blood cell. White blood cells are the primary cells responsible for fighting infections and foreign invaders in the body. Red blood cells carry oxygen to tissues, platelets help in blood clotting to prevent excessive bleeding, and plasma is the liquid component of blood that carries cells and nutrients. White blood cells, also known as leukocytes, play a crucial role in the immune system by identifying and destroying pathogens, such as bacteria, viruses, and other harmful substances. Therefore, they are the key players in the body's defense against infections, making them the correct answer in this scenario. While red blood cells, platelets, and plasma have essential functions in the body, they are not primarily responsible for combating infections like white blood cells.

5. What is the name for the change in enthalpy (heat) associated with a chemical reaction at constant pressure?

A. Entropy
B. Enthalpy
C. Gibbs free energy
D. Heat of reaction

Correct answer: D

Rationale: The correct answer is D, Heat of reaction. The heat of reaction, also known as the enthalpy change, is the amount of heat absorbed or released during a chemical reaction at constant pressure. Entropy (A) is a measure of the disorder or randomness of a system and is not specifically related to heat changes in a chemical reaction. Enthalpy (B) is the total heat content of a system and not just the change associated with a reaction. Gibbs free energy (C) is a measure of the energy available to do work in a system at constant temperature and pressure, but it is not the specific term for the heat change in a chemical reaction.