Using its long tail and long hind legs, the Ord's kangaroo rat can jump 2 m in the air as it hops away from predators, such as snakes and owls [A, 4 marks] a. How would Lamarck account for the origin of the long hind legs of the Ord's kangaroo rat? b. How would Darwin?

Answer and Explanation:

a. According to Lamarck, the origin of the long hind legs of the Ord's kangaroo rat is acquired due to extensive use of the muscle legs to jump. Such physical characteristics could be transmitted to future generations. This theory is called Neo-Lamarckism.

b. Darwin, on the other hand, theorized that in a population of Ord's kangaroo rat, there was an individual whose characteristics, long tail and hind legs, had more chances of escaping its predator and, consequently, could survive and reproduce. This theory is called Darwinism.

the answer that best describes the relative refractory period in the neuron is the resting membrane potential is restored, but concentrations of sodium and potassium are not restored to their original state.

the refractory period is the time during which another stimulus given to the neuron will not lead to a second potential. thus, because na+ channels are inactivated during this time, additional depolarizing stimuli do not lead to new action potentials.  

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thrombocytopenia, which is a deficiency in blood platelets, can cause bleeding and bruising in the dermis similar to senile purpura. other possible causes include: exposure to ultraviolet rays and aging skin are common causes of senile purpura. senile purpura may also be a sign of collagen loss in the skin and bones.