50 points !
1) the main goal of science is to:
a) collect facts and learn "the truth"
b) understand nature
c) do wild and crazy experiments
d) is to produce facts
2) an observation is received directly or indirectly by
a) hearing
b) seeing
c) tasting/touch
d) all of above
3) scientific fact can never change
a) true
b) false
4) a scientific theory
a) holds the highest level of acceptance
b) explains a number of facts
c) uses specific hypotheses and descriptive laws that have been well-tested
d) all of above
e) none of the above
5) a scientific hypothesis starts with the lowest level of acceptance but can become stronger as hey are used and survive repeated testing.
a) true
b) false

the answers are c, d, b, c, and a

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.

answer: e.   sour taste

explanation: acids are those substances which dissociates in water to give ions. as they dissociate to give ions, they act as electrolytes and thus are electrically conductive. acids are sour in taste. example: hcl

bases are those substances which dissociates in water to give ions or accepts ions. as they dissociate to give ions, they act as electrolytes and thus are electrically conductive. bases are bitter in taste. bases are slippery in nature.