Name and describe three different stem types (of plants) and how they adapt a plant to it's environment

Stems are vital part of plant as they help in transportation of nutrients and mineral salts from the soil to the leaves for photosynthesis, without which a plant cant survive. Majorly there are two types of stems that is herbaceous stems and woody or ligneous stems. Herbaceous stems are supported by water without which the plants fall and bend to the ground. Types of herbaceous stems include bulbs, runners, climbers and tubers. Most herbaceous stems are thin and green in color. Woody plants are thicker, taller and harder compared to the herbaceous stems and when fully grown they form the bark. This involves secondary growth that results in the increase of the girth and the stem becomes a trunk holding the branches and the leaves.

option a is correct i.e.

only sodium ions can pass through the membrane.

explanation:

in context to the membrane of nerve impulse, the outer membrane of neuron is semi permeable that is only sodium ions can pass through the membrane i.e. smaller ions can pass through the membrane while larger ions cannot pass through it.