Describe the effects of human contamination on invertebrate species and their stream ecosystem. Use details from the text to support your answer.

Which statement best describes the relationship between an allele and a gene? question 1 a. an allele is a variation of a gene that can be expressed as a phenotype. b. an allele is the part of a gene that attaches to messenger rna molecules. c. an allele is a segment of a dna molecule that controls replication of a gene.

Several bird species feed in a certain species of tree. each bird species feeds in a different part of the tree. which statement is true of these bird species? a. they have adapted to different niches due to competition b. they have a carnivorous relationship with the tree species. c. they have adapted to different niches due to predation d. they have a symbiotic relationship with the tree species.

What was the purpose of mendel's experiments with dihybrid crosses? a. to determine if dna was a transforming factor b. to determine if traits could be recessive c. to determine if traits affected each other d. to determine if traits had more than one allele