The answer is the first option "true." According to social exchange theory, altruistic behaviors benefit the individual who performs them is a true statement. That is because the word Altruism means doing acts to benefit themselves.
Hope this helps.
Okay, I am going to use solar prominence and solar flares.
So, Solar Prominence is a large, bright, gaseous feature extending outward from
the Sun's surface, often in a loop shape. Prominence are anchored to
the Sun's surface in the photo-sphere, and extend outwards into the Sun's
corona.
A solar flare is a sudden flash of brightness observed near the Sun's
surface. It involves a very broad spectrum of emissions, requiring an
energy release of up to 6 × 10²⁵ joules of energy (roughly the
equivalent of 160,000,000,000 megatons of TNT, over 25,000 times more
energy than released from the impact of Comet Shoemaker–Levy 9 with
Jupiter).
Hope this helps
We have millions of alveoli under our lungs, they diffuse oxygen molecules in our blood, then they get transported to every organ of our body through our Heart
Hope this helps!
Answer:
The acceleration is: 
Explanation:
To answer this, we need to recall Newton's Second Law of motion, that states that an object of mass m would accelerate (change its state of uniform motion) proportional to the force (F) that is applied , and exemplified by the following equation:

From here, and using the given values for mass (m = 3 kg) and force (F = 9 N), we can derive the value of the acceleration as shown below (notice that since all quantities are given in SI units, the resulting acceleration will also be in Si units (
):

Answer:
average speed = 66.67 km/h
Explanation:
In order to find the average speed of the train, you need to calculate the total distance traveled, divided by the time it took to cover that distance. So for the total distance:
Distance= 120 km + 180 km = 300 km
For the total time we need to add three different quantities, two of which we need to derived based on the information provided:
time for first part of the trip:

for the time of the stop:

for the last part of the trip:

Which gives a total of 4.5 hours
Then, the average speed is: 300/4.5 km/h = 66.67 km/h