Escherichia coli is plated on nutrient agar plates that each contain a different type of antibiotic. The shaded area represents the growth of the bacteria. Which of the following plates contains bacteria that were most resistant to the antibiotic?

A.

B.

C.

D.

The correct answer is C. The complementary strand of DNA will have bases that pair with the original strand according to the base-pairing rules. In DNA, adenine (A) pairs with thymine (T), and guanine (G) pairs with cytosine (C). Therefore, the complementary strand reads 3’ TCGATCGCA5’.

The correct answer is D. The scientific purpose would be to analyze the factors that led to the failure of the 1924 expedition, providing insights into mountaineering challenges and safety considerations, rather than demonstrating modern technology or exploring new routes.

The correct answer is D. Mitochondria are the cellular organelles responsible for the production of ATP (adenosine triphosphate) through the process of cellular respiration.

The correct answer is C. 9. The pH is determined by taking the negative logarithm (base 10) of the hydrogen ion concentration ([H+]). In this case, -log(10^(-9)) equals 9, so the pH of the solution is 9.

To find the pH of a solution with a hydrogen ion concentration ([H+]) of \(10^{-9}\) M using the equation \(pH = -\log[H^+]\):

\[ pH = -\log(10^{-9}) \]

Now, since \( \log(10^{-9}) = -9 \), the negative sign before the logarithm makes the value positive:

\[ pH = -(-9) = 9 \]

Therefore, the solution has a pH of 9

The correct answer is B. Objects A and B have the same mass, but B falls faster because it has less air resistance. Objects C and D have different masses, but C falls faster because it has a higher mass-to-surface-area ratio, which reduces the effect of air resistance.

Independent assortment occurs during metaphase I when homologous chromosome pairs line up randomly at the cell’s equator. This randomness contributes to genetic variation because the distribution of maternal and paternal chromosomes into gametes is different each time meiosis occurs.

The correct answer is B. Parathyroid hormone (PTH) regulates blood calcium levels by stimulating the release of calcium from bones, reabsorption of calcium in the kidneys, and absorption of calcium in the intestines. Norepinephrine, growth hormone, and melatonin do not play a primary role in calcium regulation.

The correct answer is A. This option describes a chemical reaction known as the reaction of water with sodium, producing hydrogen gas. Chemical reactions involve the breaking and forming of chemical bonds, and in this case, sodium reacts with water to produce hydrogen gas and sodium hydroxide.

The correct answer is B. The vermiform appendix is a small, tube-like structure that extends from the cecum, which is the first part of the large intestine. It is not associated with the jejunum, rectum, or ischium.

The hip bone (or pelvis) in adults is formed by the fusion of three separate bones: the ilium, ischium, and pubis. This fusion occurs during adolescence and results in a single, solid structure.