Explain why a paramecium would require contractile vacuoles while a similar protozoan living in salt water would not.

Suggest why placing wheels under a heavy box reduces the neccessary force required to push it along at a constant speed.

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.

What organ systems are working to you cool down after a workout?