We need to "eat our nitrogen"? What does it mean that we "eat our nitrogen"?

Which scientific design has both practical limitations and limitations due to scale? studying the effect of bleach on the growth of mold spores exposing cultures of duckweed to different intensities of light observing the replication of dna molecules with a hand lens using colored marbles to model a cross between two colors of rabbits

Which of the following requires the use of energy and the of transport proteins to move a molecule across a cell membrane?

Which allele is expressed in the first-generation offspring of parents that have two different traits? a. the segregated allele b. the true-breeding allele c. the recessive allele d. the dominant allele