decomposers in an ecosystem play a vital role by

ATI TEAS 7

TEAS 7 science quizlet

1. Decomposers in an ecosystem play a vital role by:

A. Photosynthesizing and producing organic matter
B. Breaking down dead organisms and returning nutrients to the environment
C. Preying on herbivores and controlling their populations
D. Fixing nitrogen from the atmosphere and making it available to plants

Correct answer: B

Rationale: Decomposers are organisms that break down dead organic matter, such as dead plants and animals, into simpler substances. By doing so, they help to recycle nutrients back into the environment, making them available for other organisms to use. This process is essential for the functioning of ecosystems, as it ensures that nutrients are not lost but instead are continuously cycled through the ecosystem. Photosynthesis (option A) is the process by which plants and some other organisms convert light energy into chemical energy in the form of glucose, and it is not a role of decomposers. Preying on herbivores (option C) is a role typically carried out by predators, not decomposers. Fixing nitrogen from the atmosphere (option D) is a process carried out by nitrogen-fixing bacteria, not decomposers.

2. What is the primary function of the spleen, an organ associated with the lymphatic system?

A. Regulating blood sugar levels
B. Filtering blood and destroying old red blood cells
C. Producing digestive enzymes
D. Secreting hormones

Correct answer: B

Rationale: The spleen is primarily responsible for filtering blood and destroying old or damaged red blood cells. It also aids in storing blood and producing specific types of white blood cells, contributing to maintaining blood quality and immune system function. Choices A, C, and D are incorrect because the spleen is not involved in regulating blood sugar levels, producing digestive enzymes, or secreting hormones. These functions are carried out by other organs in the body.

3. What is the difference between a pure substance and a mixture?

A. Pure substances have a fixed composition, mixtures don't.
B. Mixtures have a fixed composition, pure substances don't.
C. Pure substances can be in any state, mixtures are not always solids.
D. Pure substances are always elements, mixtures are always compounds.

Correct answer: A

Rationale: Pure substances have a definite and constant composition, meaning they are made up of only one type of atom or molecule with fixed proportions. This composition does not vary. On the other hand, mixtures are composed of two or more substances physically combined. The components of a mixture can be present in varying proportions, leading to a variable composition. Choice A is correct as it accurately distinguishes between pure substances and mixtures based on the fixed composition of pure substances and the variable composition of mixtures. Choice B is incorrect because mixtures, not pure substances, have variable compositions. Choice C is incorrect as both pure substances and mixtures can exist in different states. Choice D is incorrect because pure substances can be compounds as well, not exclusively elements, and mixtures can contain elements and compounds.

4. What is the term for a solution that has a lower concentration of solute compared to another solution?

A. Saturated solution
B. Unsaturated solution
C. Dilute solution
D. Concentrated solution

Correct answer: B

Rationale: An unsaturated solution is the term used for a solution that has a lower concentration of solute compared to another solution. In an unsaturated solution, more solute could still be dissolved. The other options are incorrect. A saturated solution (A) contains the maximum amount of solute that can be dissolved and is in equilibrium with undissolved solute. A dilute solution (C) has a low concentration of solute, but it does not imply a comparison to another solution. A concentrated solution (D) has a high concentration of solute compared to the solvent, which is opposite to what is described in the question.

5. What is the relationship between force and acceleration according to Newton's second law?

A. Force is directly proportional to acceleration
B. Force is inversely proportional to acceleration
C. Force has no relation to acceleration
D. Force causes deceleration, not acceleration

Correct answer: A

Rationale: According to Newton's second law of motion, the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. This relationship is mathematically expressed as F = ma, where F represents force, m represents mass, and a represents acceleration. Therefore, an increase in force will result in a proportional increase in acceleration, supporting the statement that force is directly proportional to acceleration. Choice B is incorrect as it suggests an inverse relationship, which is not consistent with Newton's second law. Choice C is incorrect because force and acceleration are indeed related as per Newton's second law. Choice D is incorrect as force can cause acceleration or deceleration depending on the direction of the force relative to the motion of the object, but it does not exclusively cause deceleration.