A neurotransmitter .

a. binds actin filaments, causing them to slide ( p p .2
b. di uses across a synaptic cleft from a neuron to a muscle cell
c. transports ATP across the synaptic cleft
d. breaks down acetylcholine at the synapse

b. di uses across a synaptic cleft from a neuron to a muscle cell.

Explanation:

A neurotransmitter is di uses across a synaptic cleft from a neuron to a muscle cell. Neurotransmitters are chemicals which enable neurotransmission.  In reaction to an impulse a motor neuron axon secretes a neurotransmitter and causes the muscle fiber to contract. It is a chemical messenger which passes on the signals across the chemical synapse.

one is through turgidity. this occurs before ground tissue ( collenchyma

and sclerenchyma cells) become well

developed to give structural support to the plant as it grows bigger. the xylem

tissue (composed of rigid tissue) of the young

plant render this support and also maintaining osmotic turgidity of the surrounding

plant cells.

condensation. good luck!