A confounding variable refers to an external effect, which modifies the influence of an independent and dependent variable. This extraneous effect is used to affect the outcome of an experimental design. The confounding variables can ruin the experiment and can generate unnecessary outcomes.
In the given case, confounding variables can be introduced by testing multiple hypotheses at a time and by using distinct kinds of soil in each of the samples.
<span>Best source of data for defining phylogenetic relationships of in line of protists that occurs hundreds of millions of years ago is called DNA sequences for ribosomal RNA. Choose the tree that symbolize the fewest evolutionary changes, either in DNA sequence comparisons or morphological characters. </span>
Answer:
The correct answer is - strata spinosum and strata basale.
Explanation:
The two strata of epidermis that are prone to the cancer are stratum basale and stratum spinosum. The stratum basale is the major stratum layer as it is only layer that can divide and mitotically active.
The other major layer that is succeptible to cancer is spinosum as it allows the maturation of the keratinocytes. The major culprit is UV light, however other causes such as radiation and arsenic can also cause cancer.
Thus, the correct answer is - strata spinosum and strata basale.
The heads of the phospholipids, which are positioned outwards on both layers, are hydrophilic. The trails of both layers are hydrophobic and face inwards, and protected by the outer layers.
