Hi. You have not shown the sections this question refers to, nor have you provided more information about those sections. This makes it difficult for your question to be answered. However, I will try to help you as best I can.
Generally speaking, we can consider that there was no growth of bacterial colonies in sections 2 and 3, because, for some reason, the bacteria was not inoculated in sections 2 and 3. What could also have happened, is that the bacteria in the sections 2 and 3 were eliminated, but the bacteria from section 1 managed to survive and form colonies.
Another possibility is that after inoculating the bacteria in section 1, you didn't handle the bacteria correctly in the other sections, leaving that bacteria to dry out and die.
Finally, the culture media in sections 2 and 3 could be inappropriate for bacteria to develop and form colonies.
Answer:
d. nitrogen-containing base
.
Explanation:
A nucleotide comprises a phosphate group, a pentose sugar and a nitrogenous base (nitrogen-containing base).
A nitrogenous base is a type of aromatic heterocyclic organic compound which essentially has nitrogen in it. The base can be a purine or pyrimidine. Purine nitrogenous bases are adenine (A) and guanine (G) while pyrimidine nitrogenous bases are cytosine (C), thiamine (T) and uracil (U).
Till the time a base is not attached to covalently linked phosphate group and a pentose sugar, it is known as nucleoside. But as soon as we attach any nitrogenous base to the nucleoside, a nucleotide is formed. So it means a nucleotide is nucleoside + nitrogenous base.
Examples are as under:
A nucleotide which has adenine as nitrogenous base is known as adenosine triphosphate (ATP) while a nucleotide which has guanine as nitrogenous base is known as Guanosine-5'-triphosphate (GTP).
The basic building blocks of matter are called atoms.
Many fruits contain specialized structures that are adaptations for The answer is D. aiding in seed dispersal.
Maple trees have fruits with "Wings" that help the gale disperse the seeds. Some flowering plants grow fleshy fruit that benefits disperse their seeds. When animals eat the fruit, the seeds pass through an animal's digestive tract undamaged.
Explanation:
But researchers in Israel have done a study showing that families have characteristic facial expressions, ones even shared by blind members of the families. The results suggests that such expressions may be inherited and thus under some genetic control.
