When you try to remember a series of digits, you are using:

a. flashbulb memory.
b. echoic memory.
c. long-term memory.
d. short-term memory.

The answer is D. Short-term memory.

Explanation:

Short-term memory.  active memory, or primary memory is where information gathered and may be recalled briefly, if not rehearsed. Usually, the brain gathers this information through hearing, even translating visual signals to auditory information. It is also very limited as it's known to only hold a maximum of seven + two kinds of data in a single instance, and lasts 20-30 seconds only. This brief memory may be verified by letting the person recall the series of digits backwards and only recalling the last 3 digits.

to prevent people from getting the ebola virus, countries around the world paid to doctors develop a new vaccine. now that the vaccine has been made, doctors will need to experiment on a large number of people to find out if it works safely.

what is the greatest limitation that scientists are dealing with as they try to figure out how to experiment with the ebola vaccine?

meditation is a practice of sitting still and quiet for minutes or even hours. it has been practiced for thousands of years and is even a part of religious practices for some people. carefully controlled, repeated measurements of brain activity have shown that meditation does increase certain chemicals in the brain and even grows the part of the brain that people connect with their current surroundings and activities.

are claims about the effects of meditation most likely scientific or pseudoscientific?

not pseudoscientific, because people have made claims about it but scientific observations have not been made

when in a crucial situation, after calling 911, the correct posture for delivering effective compression is the proper hand placement.

first, place two fingers at the sternum, then put the heel of your other hand next to the fingers and place hand on top of the other. lock your elbows by using your body’s weight and compress the victim’s chest with a depth of 2 inches.

moreover, do 15 compression and 2 breaths, this process must be done four times until there is a pulse or a arrive.