What sentence contains the present participle of the verb to collect.
a. he has collected rare coins.
b. he is collecting rare coins.

The sentence that contains a present participle of the verb to collect is sentence B.

Explanation:

A participle typically expresses present action with respect to the time expressed by the finite verb in its clause and that is formed by adding the suffix -ing. The present participle is used in the formation of the progressive or continuous tenses.  In the sentence above, you can see that the event is taking place now if you add now  (see A).

a) He is collecting rare coins now

this is the answer , p = 1 + (1/10)x

step-by-step explanation:

we have,

at sea level pressure is 1 atmosphere (i.e at x =0, p0=1 atmosphere)

at depth 23 meters , pressure = 3.3 atmosphere

since the pressure increases at constant rate as the depth increases, so we can write a relation as:

p =p0 +   kx   , where p is the pressure  , p0 is the initial pressure, x is the depth and k is constant rate of increasing.

to find constant rate k, plug p = 3.3 , p0 = 1 and x= 23 meters

we get,

  3.3 = 1 + k * 23

k = 2.3 / 23   = 1/10

so we can write the function formula as:   p = 1 + (1/10)x

my answer is the spanish won