On a molecular level, all organisms
a. have the same bases in dna and rna, the same amino acids in proteins, but use different genetic codes.
b. have the same bases in dna and rna, the same amino acids in proteins, and use the same genetic code.
c. show no similarities.
d. have the same bases in dna and rna, but different amino acids in proteins.
e. use different means of storing genetic information.

Are substances released into the environment that in excess amounts cause damage

Which type of organism is missing from the food web seen in the illustration? primary consumers decomposers primary producers secondary consumers

1. emigration the movement of people from one place to another 2. immigration a situation in which resources are being used up at a faster rate than they can be replenished 3. migration the leaving of one's homeland to settle in a new place 4. overpopulation the movement of people to a new country 5. sustainable development a situation in which the birth rate is not sufficient to replace the existing population 6. underpopulation the ability to meet current needs without reducing the ability to meet future needs 7. unsustainable development the increase in the population of a city 8. urbanization a situation in which the number of people exceeds the available natural resources in an area