Typical animal embryos have a(n) , or external cell layer, and a(n) , which lines the digestive tract.

Spring tides, when the high tides are at their highest and low tides at their lowest. what is it about these positions that causes these high and low tides?

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.

This group of organisms perform the process of ammonifcation. a. herbivores b. decomposers c. carnivores c. plants