5. a. Identify and name the rock in the picture below. b. How is it formed?
c. Why it is called a porous rock?
d. Give two uses of the rock.

a) The rock above shown in the picture is pumice rock because it is having abundant pores on its surface. It is the only rock found with numerous pores.

b) The pumice rock is an igneous rock and we know that igneous rocks ar made from the molten magma. When the lava comes out, and cooled down it forms the igneous rocks. During this process, if there are air spaces accumulated, they form pumice rock.

c) The pumice rock is known as porous rock because it contains many pores due to air spaces inside it. This is h hence very light and floats on water.

d) The pumice rock is used as a scrubber because of its lightness and porosity. It is also used as an abrasive

#CarryOnLearning

━━━━━━━━━━━━━━━━━━━━

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.  

read more on -

this age may represent the age of the earth's accretion, of core formation, or of the material from which the earth formed. this dating is based on evidence from radiometric age-dating of meteorite material and is consistent with the radiometric ages of the oldest-known terrestrial and lunar samples.