If the atoms that are bonding have identical electronegativities, then it's a completely nonpolar covalent bond. This doesn't happen in the real world unless the two atoms are of the same element. In a practical sense, any two elements with an electronegativity difference less than 0.3 is considered to be nonpolar covalent.
As the difference between the atoms increases, the covalent bond becomes increasingly polar. At a polarity difference of 1.7 (this changes depending on who you ask) we consider it no longer to be a covalent bond and to be the electrostatic interactions characteristic in an ionic compound.
Just so you know, you shouldn't take these values as exact. ALL interactions between adjacent atoms involve some sharing of electrons, no matter how big the difference in electronegativity. Sure, you wouldn't expect much sharing in KF, but there's a little sharing of electrons anyway. There's certainly no big cutoff that happens at a difference of 1.7 Pauling Electronegativity units.
Zoom in on pic so I can answer for you
An organism must has a large surface area to volume ratio in order to exchange material easier
in animals erythrocytes have a flat concave shape that allows them to carry more haemoglobin and also increases its surface area to volume ration so that the length and availability of a surface is less for the materials to travel
multi cellular organisms tend to have flat and elongated respiratory surfaces to allow for a higher surface area to volume ratio in order to increase the rate of gas exchange
the ilium in most mammals is flat and elongated and is covered with microvilli to increase surface area and to reduce the cells volume therefore reducing its surface area to volume ratio
hope that helps
Answer:
Homologous structures
Explanation:
Features that are similar in structure, but appear in different organisms and may have different functions
Answer:
the specific function of glucose is that it helps in the circulation of blood. It can also be considered as the source of energy in cell function and regulations of metabolism.
