Which statement correctly describes a physical change?
o a. involves breaking and creating chemical bonds but not changing a phase
o
b. may involve a change in phase but does not involve a change in the molecular structure
o
c. may involve converting two or more substances into new substances
od.
involves changes at the molecular level
o e.
involves energy transfer and change in color
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Citric acid has a ph between 1 and 3.  it is considered to be aa. weak acidb. weak basec. strong based. strong acid

Which of the following is not an assumption that scientists must make about the natural world? a. regularity b. causality c. predictability d. plausibility

Ascientist wants to know how individual lions within a pride interact with each other in their own environment. to do this, the scientist sedates and tags all of the lions within a pride. then, he places several remotely-controlled video cameras near the lions' den and performs an observational field study. he collects continuous video footage over the span of one year, analyzes the video, and then forms conclusions based on his observations.