By studying fossils, scientists can learn how much (or how little) organisms have changed as life developed on Earth. There are gaps in the fossil record because many early forms of life were soft-bodied, which means that they have left few traces behind. This is why scientists cannot be certain about how life began.
<em>Hardness is a measure of how resistant solid matter is to various kinds of permanent shape change when a force is applied</em> <em>Macroscopic hardness is generally characterized by</em> <em>strong intermolecular bonds</em>, <em>but the behavior of solid materials under force is complex; therefore,</em> <em>there are different measurements of hardness</em>: <em>scratch hardness, indentation hardness, and rebound hardness. Hardness is dependent on ductility, elastic stiffness, plasticity, strain, strength, toughness, viscoelasticity, and viscosity. Common examples of hard matter are ceramics, concrete, certain metals, and super hard materials, which can be contrasted with soft matter.</em>
Helium does not react with any other substances, thus the substance’s internal structure is never greatly affected and thus helium cannot have any chemical properties.
Answer:
C) They are compressed during inhalation.
Explanation:
Birds breathe through rigid lungs that are located in the animal's thoracic region. The trachea of birds divides into bronchi that branch inside the lungs into very thin tubes called parabronchials or parabroncholes, which are irrigated by blood capillaries that allow gas exchange.
In birds there are no pulmonary alveoli (as in mammals), but air capillaries that depart from the parabroncholes. Oxygen gas passes from these capillaries to the blood capillaries, thus causing gas exchange.
In the lower portion of the bird's trachea, before branching the bronchi, we can find the syringe, a bag-like structure that has vocal cords responsible for the birds' scream and song. Most of the time, the sound emitted by birds serves to attract the mate, mark territory and prevent birds of the same species against some predator or other danger.
Answer:
depended on applications of fertilizers, pesticides and irrigation to create conditions in which high-yielding modern varieties could thrive.
Explanation:
