The bird's eye contains a nictitating membrane which is a translucent, semitransparent inner eyelid. It sweeps across the surface of the eye enabling the bird to blink without losing sight of or without blocking their view.
Birds also have two different tear glands. One type of tear gland is located along the lower eyelid while the other is located at the base of the nictitating membrane. The second tear gland lubricates the bird's eyes whenever the nictitating membrane blinks.
Answer:
Water (H2O) can be called a molecule or a compound because it is made of hydrogen (H) and oxygen (O) atoms. There are two main types of chemical bonds that hold atoms together: covalent and ionic/electrovalent bonds. Atoms that share electrons in a chemical bond have covalent bonds.
When RNA from a specific strain of TMV is mixed with coat protein from the same strain, infectious virions are formed. I think the correct answers are the following:
A hybrid virus is also avirulent.
All necessary information is present in the DNA.
Its DNA is completely covered with a coat protein.
