According to the problem we need density and frequency.
Density is defined as the number of individuals per area unit. Meanwhile, frequency is the probability of finding a species in a certain area.
The formulae are as it follows
Density (D)= Total of individuals/ sampled area
Frequency (Fr)= (Number of quadrants where species is present/ total number of quadrants)X100
Applied for (i)
Plants= 2+6+7+12+3+5+5=40
Sampled Area: (10x4m²)= 40m²
D=40/40m²=1 individuals/m²
Applied for (ii)
present in 7 quadrants
total of quadrants 10
Fr=(7/10)x100
=70%