The Doppler effect is the term that best describes the change in frequency of waves when there is motion between the source of the waves and the observer. The correct option among all the options that are given in the question is the first option or option "a". I hope the answer helps you.
CORRECT ANSWER:
a- Cell-surface receptors bind polar signaling molecules; intracellular receptors bind nonpolar signaling molecules.
STEP-BY-STEP EXPLANATION:
The complete question from book is
According to Figure 9.6, what is a key difference between cell signaling by a cell-surface receptor and cell signaling by an intracellular receptor?
a- Cell-surface receptors bind polar signaling molecules; intracellular receptors bind nonpolar signaling molecules.
b- Signaling molecules that bind to cell-surface receptors lead to cellular responses restricted to the cytoplasm; signaling molecules that bind to intracellular receptors lead to cellular responses restricted to the nucleus.
c- Cell-surface receptors bind to specific signaling molecules; intracellular receptors bind any signaling molecule.
d- Cell-surface receptors typically bind to signaling molecules that are smaller than those bound by intracellular receptors.
e- None of the other answer options is correct.
Answer:
The amplitude of the subsequent oscillations is 13.3 cm
Explanation:
Given;
mass of the block, m = 1.25 kg
spring constant, k = 17 N/m
speed of the block, v = 49 cm/s = 0.49 m/s
To determine the amplitude of the oscillation.
Apply the principle of conservation of energy;
maximum kinetic energy of the stone when hit = maximum potential energy of spring when displaced

Therefore, the amplitude of the subsequent oscillations is 13.3 cm
The options missing are;
A. Make only a few changes to the manipulated variable.
B. Identify any biases about the answer to the scientific question.
C. Include as many details as possible when writing the conclusion.
D. Share her ideas through peer review.
Answer:
B. Identify any biases about the answer to the scientific question.
Explanation:
Since the question is asking what can be done to improve the quality of the results, it means what can the scientist do to make sure that the result answers the question properly and has little or no biases.
Thus, looking at the options, the only one that comes close to actually improving on the quality of the results before finalizing is option B where the scientist is to identify any biases.
Answer:
creo que es la opcion numero 4.