Answer:
D.-
Explanation:
A control group is needed to carry out the experiment, that control group is the one that is not injected with anything. Ethanol and pesticide need to be injected into separated groups to document whether it is one or the other that is harmful
Answer:
D. structures that have lost all or most of their function over evolutionary time
Explanation:
the question states that the leg bones are almost entirely unused because of evolution
C. Sedimentary Layers, sedimentary rocks are created as a result of high pressure :)
I hope this helped!
Answer:
B) an error occurred, the mass of the reactants should equal the mass of the products.
Explanation:
The answer choices are:
A) no error occurred, some of the products are always lost as heat.
B) an error occurred, the mass of the reactants should equal the mass of the products.
C) an error occurred, the products should weigh more than the reactants.
D) no error occurred, water is not weighed when determining the weight of the products.
Solution
The basis to answer this question is the law of conservation of mass.
Any chemical reaction satisfies the law of conservation of mass: mass cannot be either created nor destroyed, so, always, the mass of the reactants equal the mass of the products.
Thus, since he measured the mass of his reactant materials to be 35g and he reported that his products weighed 32g, his data are in clear contradiction of the law of conservation of mass. So, there is an error in his results: the mass of the reactants should equal the mass of the products.
