What is one drawback of using evidence found in rock layers to determine a relative history of the earth? 1. not all organisms leave fossils 2. not all layers contain salt deposits 3. all areas of earth have distinct rock layers 4. rock layers are never disturbed

Plz genetic engineering can be applied to many fields including medicine and agriculture. which of the following is a medical application of genetic engineering? a. giving crop plants recombinant dna so that they would be resistant to herbicides. b. examining a persons pedigree to determine whether they can carry a gene for a genetic disease. c. analyzing a persons dna to see how closely they are related to another person. d. certain genes into bacteria so that they will produce a needed medicine.

The fruit of a certain plant is sweet and fleshy. the seeds of this plant have a seed coat that is fairly tough. the seeds germinate better if they are exposed to acid, or scarification. what is the most likely type of dispersal for this seed? water animal wind

This is a situation in which genes are attached to an organism's sex chromosomes; the sex of an organism influences the expression of a gene.