The answer is; A
This is a symbiotic relationship. The mycorrhiza is harbored I the roots of the orchids. The fungi nitrify the soil around the plant. Therefore, the fungi make nitrates (which are critical for the growth of the plant) available to the plant. The fungi, on the other hand, are assisted in breaking down of large carbon polymers by the orchids because the plant’s enzyme is more powerful than those of the fungi.
Answer:
The magnetic field due to a solenoid is given as : where, is the permeability of the medium. n is the number of turns or loops in the coil. I is the current flowing in the solenoid.
The magnetic field due to a solenoid can be increased by increasing the number of turns, current and placing an iron core inside the solenoid.
So, the correct option are:
(1) using more wire loops
(2) using a larger current
Hence, the correct options are (a) and (c).