The definition of symbiotic is O Having tiny tentacles
O consisting of two oxygen atoms
O having a hard external covering
O living in close association

The answer is D.

Explanation:

involving interaction between two different organisms living in close physical association.

Example:"the fungi form symbiotic associations with the roots of plant species"

answer: they produce more slow than unicellular organisms.

answer: semi-infinite solid initially at a uniform temperature of 400 ◦c is cooled at its surface by convection. the cooling fluid at a constant temperature of 200 ◦c has a convective coefficient (ha) of 250 w/m2.k. the physical properties of the solid: k = 20 w/m.k and α = 4 * 10-5  m2/s. using δx = 0.04 m and δt = 10 s. write the finite difference equations describing the transient heat transfer of the first five δx and the temperature profile after 30 s.