AZSCI Stability and Change

Question 1

The human body sweats when it gets too hot and shivers when it gets too cold. These responses are examples of the body trying to maintain a stable internal temperature. What is this process called?

Accepted Answer

Homeostasis

Answer

Homeostasis is the process by which biological systems maintain a stable internal environment despite changes in external conditions. Regulating body temperature is a classic example of a homeostatic mechanism.

Question 2

A forest ecosystem can remain relatively unchanged for hundreds of years. Which of the following would most likely disrupt the stability of this ecosystem and cause significant change?

Accepted Answer

The introduction of an invasive insect species

Answer

Introducing a non-native (invasive) species can drastically disrupt an ecosystem's stability. The new species may have no natural predators, outcompete native species for resources, and cause a cascade of changes throughout the food web.

Question 3

In a reversible chemical reaction, equilibrium is reached when...

Accepted Answer

the rate of the forward reaction equals the rate of the reverse reaction.

Answer

Chemical equilibrium is a state of dynamic balance, not a state where the reaction has stopped. It is achieved when the rate at which reactants are forming products is exactly equal to the rate at which products are reverting to reactants. This results in no net change in the concentrations of substances.

Question 4

The rock cycle describes how rocks are continuously formed, broken down, and reformed into different types (igneous, sedimentary, metamorphic). This cycle is best described as a system in...

Accepted Answer

a state of dynamic equilibrium over geologic time.

Answer

The rock cycle represents a system that is constantly changing over vast geological timescales, yet it follows a predictable, cyclical pattern. This is a form of dynamic equilibrium, where change is constant but the overall system persists.

Question 5

The melting of Arctic sea ice exposes darker ocean water. This darker water absorbs more sunlight than the reflective ice, causing further warming and more ice to melt. This is an example of a:

Accepted Answer

positive feedback loop.

Answer

This is a positive feedback loop. An initial change (melting ice) causes an effect (more heat absorption) that amplifies the original change, leading to even more melting. Positive feedback loops drive systems away from stability.

(AZSCI) Arizona Science Test Practice Test

(AZSCI) Arizona Science Test Practice Test

AZSCI Stability and Change