Explain why flatworms do not need a respiratory or circulatory system

Why are nails made of iron and not barium and phosphorus?

What should scientist study to prevent viruses

Which of these carbohydrates is not broken down by our bodies? glycogen amylose fiber amylopectin?

Of what is this an example? A puppy's cells have two sex chromosomes that are the same. homozygous dominant homozygous recessive heterozygous female

All of the following are characteristics of a developing countries except

Mendel hypothesized that gametes have only one factor or allele for each inherited trait. This hypothesis is supported by the observation that A) diploid cells are produce by meiosis. B) haploid cells are produced by meiosis.

The plasma membrane is composed of several different macromolecules which macromolecule serves as the fluid interface between the intracellular and extracellular environments

The table above shows five different types of chromosomal abnormalities that can occur during meiosis. They result in either an individual having too many or too few chromosomes in their genome.

During which stage of disease should an infected person be considered contagious

A scientist observed the boundrary between teo tectonic plates for a decade and finds that no new volcanoes have formed over the course of her investigation. Does this result suppor the theory of plate tectonic? Why or why not?