Question

select the correct answer.
giselle is working with a chemical substance in a laboratory. she observes that when the chemical is heated, it gives off a gas. she assumes that the gas is oxygen but decides to test this assumption to verify it. which type of scientific knowledge is giselle’s assumption?
a. fact
b. hypothesis
c. law
d. observation
e. theory

Explanation:

• A fact is a confirmed observation. Giselle's assumption isn't confirmed yet, so A is wrong.
• A hypothesis is a proposed explanation to be tested. Giselle assumes the gas is oxygen and will test it, so this fits.
• A law describes a natural phenomenon, not an untested assumption, so C is wrong.
• An observation is what's seen (like the gas being given off), not an assumption, so D is wrong.
• A theory is a well - supported explanation, not an untested assumption, so E is wrong.

Answer:

B. hypothesis