The answer is oil.
The United States' fossil shortage of oil makes the country dependent on outside sources. Mineral oil such as crude oil or commonly known as petroleum came from the ancient fossilized organic materials. This resource is limited. The US is now facing a shortage in oil and becoming dependent to some countries such as middle-east countries.
Answer:
Changes in the environment may leave individuals less well adapted to compete successfully for resources such as food, water and mates. Sometimes an entire species may become unable to compete successfully and reproduce. These problems can lead to extinction.
Explore a wide variety of cells, from bacteria to human neurons, using a compound light microscope. Select a sample to study, then focus on the sample using the coarse and fine focus controls of the microscope. Compare the structures found in different cells, then perform tests to see if the sample is alive.
<span>Germination of a diploid zygospore followed by meiosis produces 4 haploid cells</span>
The right answer is polarity.
In chemistry, polarity is a characteristic describing the distribution of negative and positive charges in a dipole. The polarity of a bond or a molecule is due to the difference in electronegativity between the chemical elements that compose it, the differences in charge that it induces, and to their distribution in space. The more the charges are distributed asymmetrically, the more a bond or molecule will be polar, and conversely, if the charges are distributed in a completely symmetrical manner, it will be apolar, that is to say non-polar.
Polarity and its consequences (van der Waals forces, hydrogen bonding) affect a number of physical characteristics (surface tension, melting point, boiling point, solubility) or chemical (reactivity).
Many very common molecules are polar, such as sucrose, a common form of sugar. The sugars, in general, have many oxygen-hydrogen bonds (hydroxyl group -OH) and are generally very polar. Water is another example of a polar molecule, which allows polar molecules to be generally soluble in water. Two polar substances are very soluble between them as well as between two apolar molecules thanks to Van der Waals interactions.
