Which of the following is am example of adaptive radiation?
(a)one population of squirrels becomes two separate species over a long time,
(b) one population of lizards leads to 15 separate species over a short time,
(c)one species of birds becomes better suited to its environment over time.
(d) two species of fish to breed with each other.
-if correct you will get brainless

The correct answer is (B) One population of lizards leads to 15 separate species over a short time.

Adaptive radiation is a process of macro-evolution in which one specific life form is rapidly diversified into another new life forms when it encounters changing environmental conditions.    

Thus, when one population of lizard leads to 15 separate species over a short time, it reflects adaptive radiation.      

Example- Darwin's finches on galapagos island, which were adapted for different feeding behavior is the example of Adaptive radiation.

1) a giant star is a star with a radius much larger than that of our sun (even hundreds of times bigger). they can be either blue giants or red giants: in the first case, the surface temperature is very high, higher than that of the sun, while in the second case the surface temperature can be lower than that of the sun. the same applies to the mass: blue giants are very massive stars, burning quickly their nuclear fuel, while red giants can have small masses (a little bit bigger than that of our sun).

2) we can find giant stars in the upper part of the hr diagram, blue giants will be on the upper left corner since they have high luminosity and high temperature, while red giants will be on the upper right corner, having high luminosity but low temperature.