Asingle motor neuron and the population of muscle fibers that it innervates is called a(n):

Motor unit

Explanation: Motor unit is a term used to describe a single motor neuron innervating the fibers of skeletal muscles. The axon endings of this motor neuron is in contact with the muscle fibers. The fibers in the motor unit are all of the same kind, but the number can vary from muscle to muscle. Activation of the motor unit causes contraction of the muscle fibers.

1: most common garden plants prefer loam — soils with a balance of different-sized mineral particles (approximately 40% sand, 40% silt, and 20% clay) with ample organic matter and pore space. however, some plants grow better in sandy soils, while others are well-adapted to clay soils.

2: available water capacity is the maximum amount of plant available water a soil can provide. it is an indicator of a soil's ability to retain water and make it sufficiently available for plant use. available water capacity is the water held in soil between its field capacity and permanent wilting point.

3: it is the same for all living things (plants and animals). it also includes very tiny organisms that our eyes cannot see. they are known as microorganisms, and include viruses, bacteria and fungi.