C. Some studies can be unethical to carry out in an experimental framework.
Step-by-step explanation:
Sometimes it is not possible for researchers to carry out the development of an experimental framework, since the full well-being and integrity of its participants may not be assured in the implications that must be taken into account for its application.
For this reason they could be considered unethical since they threaten the individual or his environment in some way. For example, in the medical field, it is very important to take special care with this type of research to ensure the well-being and health of the individuals involved, due to the fact that any failure in the application of such experiments could even result in the death of any of the individuals. .
First let's find the result of the sum: 30 + 40 + 70 = 140 Now let's review the operations of each one: Jillian added 30and40and then 70: 30 + 40 = 70 70 + 70 = 140 Samuel added 30 and 70 and then 40 30 + 70 = 100 100 + 40 = 140 answer both are correct. Conclusion: the order of the factors does not alter the product.