What is any factor that makes it difficult for a new firm to enter a market referred to as?
a. a sustainable cost
b. a commodity
c. a barrier to entry
d. perfect competition

Where do the respiratory and circulatory systems meet? a. in the heart b. in the muscles c. in the lungs d. in the brain

The concept of keystone species is controversial among ecologists because most organisms are highly interdependent. if each of the trophic levels is dependant on all others how can we say one is most important

Recombinant dna (rdna) creates offspring which are genetically identical to the parent is the process of breeding only organisms with desirable traits involves the removal of the nucleus of a cell combines genes from organisms of different species in a lab