Answer:
Louis Pasteur, by observing that the microbes were in the air and contaminated the broth helped determine that all the cells came from pre-existing cells (option b), one of the postulates of the cell theory.
Explanation:
Louis Pasteur's experiments, conducted around 1860, showed that unicellular organisms appeared in a culture broth only if it was exposed to the air, where other microorganisms were present, thus disproving the hypothesis of spontaneous generation.
On the other hand, in the broth that was not exposed to the air Pasteur did not observe microorganisms.
By rejecting the hypothesis of spontaneous generation through his experiment, Louis Pasteur reaffirmed the postulate of the cell theory that proposes that all cells come from preexisting cells.
The other options are not correct due to:
<em> a and c. </em><em><u>All animals are made of cells
</u></em><em> and </em><em><u>cell is the basic functional unit of living things</u></em><em> are postulates of the cellular theory that were not demonstrated by Pasteur's experiment.</em>
<em> d. </em><em><u>Unicellular organisms inherit an exact copy of DNA from the parent cell</u></em><em> is not a postulate of cell theory.</em>
Answer:
The first option
Explanation:
The first option because in the water cycle, water does not change chemically but, it changes its physical form throughout the cycle. In other chemical cycles ,the element (such as carbon) changes chemically throughout its cycle making it the main difference between the water cycle and other chemical cycles.
Melanin provides pigmentation to the skin and it also provides UV ray protection (which is its role in the epidermis).
Answer:
B
Explanation:
We never see short bristle males, suggesting some type of lethality. I.e. any males who inherit the mutation die before birth so we don't see the phenotype. This also hints that it could be X-linked.
Females can be short bristled, but males can't, as it is likely lethal. This suggests that having one copy of the short bristle trait without the long bristle trait is lethal (as males as XY and so only have one copy of the trait). The female then must be heterozygous for the short bristle trait (which also explains how in generation F2, long bristle males can be produced, as if she was homozygous males would all be short bristled, and therefore dead, so there would be no males.
Since the first short bristle female is heterozygous, the trait for short bristles must be dominant.
However, since evidence suggests the trait is X-linked, it cannot be autosomal, as suggested in B.
Answer:
true
Explanation:
This generally is due to either a lack of oxygen in the blood or extremely cold temperatures. When the skin becomes a bluish color, the symptom is called cyanosis. Most commonly, blue hands are caused by a lack of oxygen in the blood.
