Green plants form the base of the food chain.

As a general rule, the more developed the country, the more of its diet is from plant foods.

Climatic systems are often dependent upon the environment in which a plant grows.

Bryophytes belong to the subkingdom Embryobionta.

The first part of a binomial name states the genus of the plant.

Monocotyledoneae have one cotyledon in the seed.

Cultivar names should be underlined and capitalized.

There are relatively few root hairs found at the tips of the roots.

The aerial roots of epiphytes attach the plant to its host and absorb water from the air.

A node is the point on a stem where a leaf is or was attached.

In pinnate venation, the principal veins extend from the petiole near the base of the blade, similar to the bones in the hand.

The leaves are the sexual reproductive part of angiosperm plants.

With cymose inflorescences, the first flower to open is at the tip.

The essential organs on a flower are the stamens and pistil.

Perfect flowers always have stamens, pistils, sepals, and petals.

One of the characteristics of angiosperms is that their seeds are enclosed in a fruit.

The forces of water and wind help to create soil.

Alluvial fans form atop and within mountain ranges.

Deltas tend to have large particles and tend to be dry.

Organic soils contain less than 20 percent organic matter, except for a surface layer of plant debris.

Leaching tends to reduce phosphorus.

The organic matter content of U.S. soils tend to increase from east to west.

Desert soils have the least organic matter.

Although as many as twenty chemical elements have been identified in certain plant parts, only eight have been found to needed for plants to grow and mature properly.

A plant's leaves will often turn yellow if the plant does not get enough nitrogen.

Only about 20 percent of the nitrogen added to the soil is used by crops.

Ammonium and organic forms of nitrogen move primarily in runoff water.

Phosphorus is very immobile in the soil.

The maximum availability of phosphorus in the soil occurs under very alkaline soil conditions.

The largest known potassium deposit is in Mexico.

Molybdenum controls the synthesis of indoleacectic acid, which dramatically regulates plant growth.

Boron primarily regulates the metabolism of carbohydrates in plants.

As calcium, magnesium, and potassium are removed from the soil, the soil becomes more alkaline.

For field crops, soil portions should be collected at random from eight to ten locations.

About 16 tons of manure are produced for each ton of livestock per year.

Erosion is important in agriculture because it removes the B horizon.

The compaction effect can be affected by management factors such as the nutrient status of the soil.

Water is considered the universal solvent.

Normal precipitation remains steady throughout the year.

Water is directly proportional to the surface area exposed to air.

Too little moisture can damage plants, but too much moisture is not a problem.

About 40 percent of all water that enters plants from the roots is given off during transpiration.

Transpiration is driven by a tremendous force the atmosphere exerts on soil and plant surfaces, but evaporation is not.

The goal for irrigation managers is to convert water to ET and ultimately to yield.

Potential ET estimates crop weather use for the region around the weather station.

The feel method measures soil water more precisely than electrical resistance blocks.

When the chances of rainfall occurring shortly after irrigation are good, complete recharge of the root zone is not advisable.

Cool season vegetables can be made to adapt to somewhat cooler temperatures by gradually exposing the young transplants to stress.

If the temperature is higher than needed, photosynthesis slows down.

Growing degree days are used to estimate the growth and development of plants and insects during the growing season.

All forms of growing degree days have a common principle: that the biological process of interest begins once a certain degree of humidity is reached or exceeded.

The reliability of a GDD rating system decreases with the number of years that local GDD data have been collected.

All plants have both an optimal temperature at which they function the best, and a minimum temperature tolerance below which the plant may be injured.

The longer the wavelength of visible light, the more violet the color.

When zinc is exposed to ultraviolet light, it becomes positively charged.

Plants are the primary source of oxygen worldwide.

Light energy is not converted very efficiently to chemical energy during photosynthesis.

The longer the day, the more photosynthesis takes place.

Plants do not produce any carbon dioxide by their respiration.

The glucose manufactured during photosynthesis does not accumulate to any marked degree in most green plant cells as glucose.

All living material is made of cells or the chemical products of cells.

All organisms, regardless of their complexity, begin as a single cell.

The two strands in a DNA molecule are connected by rungs of nitrogen-containing chemicals called nucleotides.

Each time a cell divides into two daughter cells, half of the genome is duplicated.

All living organisms are composed largely of proteins.

Most flowers have just two or three pistils.

Seeds are living organisms in a dormant or inactive state.

The most common method of asexual or vegetative reproduction is propagation by cutting.