Pls ! this is the jaw of the ancient saber-toothed cat, an ancestor of the modern tiger. you can see that the teeth of the saber tooth were nearly twice as large as the teeth of today's tigers. these teeth were so large that they stuck out the the saber-tooth's mouth when it was closed. their food included large mammals such as elephants, rhinos, and other huge herbivores. what change in the environment could have led to the gradual development of the smaller front teeth we see in the modern-day tiger?

a) there was a change from tropical forests to grasslands.

b) competition from other big cats such as lions, cheetahs, and leopards.

c) the disappearance of the huge herbivores that saber toothed tigers hunted.

d) the large teeth were no longer an advantage for catching prey and survival.

The particle in a two-dimensional well is a useful model for the motion of electrons around the indole ring (3), the conjugated cycle found in the side chain of tryptophan. we may regard indole as a rectangle with sides of length 280 pm and 450 pm, with 10 electrons in the conjugated p system. as in case study 9.1, we assume that in the ground state of the molecule each quantized level is occupied by two electrons. (a) calculate the energy of an electron in the highest occupied level. (b) calculate the frequency of radiation that can induce a transition between the highest occupied and lowest unoccupied levels. 9.27 electrons around the porphine ring (4), the conjugated macrocycle that forms the structural basis of the heme group and the chlorophylls. we may treat the group as a circular ring of radius 440 pm, with 20 electrons in the conjugated system moving along the perimeter of the ring. as in exercise 9.26, assume that in the ground state of the molecule quantized each level is occupied by two electrons. (a) calculate the energy and angular momentum of an electron in the highest occupied level. (b) calculate the frequency of radiation that can induce a transition between the highest occupied and lowest unoccupied levels.

Agroup of students were investigating the force of gravity. they began by dropping a foam ball from a height of 3 meters into a bucket of sand. the ball hit the sand in 0.306 seconds. they dropped additional balls of approximately the same diameter, but of different masses. here is the data they collected. based on this experiment and the collected data, what would their conclusion be?

If angle "a" is 25°, angle "b" is: a) equal to angle c b) less than angle c c) greater than angle c