Answer:
b Different amounts of food samples were used.
Explanation:
The mass of the two samples needs to be the same in order for the test to be accurate.
Answer:
The correct answer will be option-D.
Explanation:
The semi-conservative mode of replication is the common method of replication used by mostly organisms on earth which were demonstrated by the Meselson and Stahl in 1958.
They used the isotopes of the nitrogen which contains extra neuron which makes the nitrogen-heavy and cultured them in bacteria
The experiment concluded that newly replicated double stranded DNA contains one newly synthesized DNA strand which is complementary to another parental strand. Thus new DNA molecule has one parental strand while other newly synthesized strand.
This is best illustrated by the option-D in the figure and therefore is the correct answer.
Answer:
5.25 moles.
Explanation:
The decomposition reaction of NaN₃ is as follows :
We need to find how many grams of N₂ produced in the process.
From the above balanced chemical reaction, we conclude that the ratio of moles of sodium azide and nitrogen gas are 2 : 3.
2 moles of sodium azide decomposes to give 3 moles of nitrogen gas. So,
3.5 moles of sodium azide decomposes to give 
moles of nitrogen gas.
Hence, the number of moles produced is 5.25 moles.
Answer: The final temperature will be 
Explanation:
To calculate the specific heat of substance during the reaction.
where,
q = heat absorbed =41840 J
c = specific heat = 
m = mass of water = 200 g
= final temperature =?
= initial temperature = 
Now put all the given values in the above formula, we get:
Thus the final temperature will be
Answer: Biological Magnification
Explanation:
Organisms acquire toxic substance from the environment along with nutrients and water. Some of the toxins are metabolized and excreted, but others accumulate in specific tissues, especially fat. One of the reasons accumulated toxins are particularly harmful is that the become more concentrated in successive trophic level of the food web, this is the process of biological magnification.
Magnification occurs because the biomass at any given level is produced from a must larger biomass ingested from the level below. Thus the top-level carnivores tend to be the organism most severely affected by toxic compounds in the environment.
Examples of toxins that demonstrate biology magnification are chlorinated hydrocarbons, and many pesticides.
