Answer:
A. 3/16
Explanation:
The four possible outcomes for Stem length are:
Tt, tT, TT and tt.
The dominant trait (tall stems) will manifest itself in 3 out of 4 outcomes, so its ratio is 3/4.
The four possible outcomes for flower coloration are:
Rr, rR, RR and rr.
The non-dominant trait (white flowers) will manifest itself in 1 out of 4 outcomes, so its ratio is 1/4.
Multiplying both ratios gives us the ratio of offspring that have tall stems and white flowers:

Therefore, the answer is A. 3/16
Dendrite; axon; synapse
These are parts of the neuron which is considered as the basic unit of nervous system. The cell responsible for receiving sensory input from the external environment. The stimulus will be transported in an electrical signal via neuronal parts. Axon transmit signal to the other neuron. Dendrites are the receiving part of the neuron. Synapse is the space between each neuron where elctrical impulse is converted into a chemical signal via neurotransmitters.
Organism is the smallest unit of organization.