1.A race of inbred plant has a mean petal length of 12 mm, a second race from another location has the same meant petal length. when the two races are crossed, the F1 also has the mean petal length of 12mm. however the F2 generation derived from crossing the F1 to one another shows a very wide spread in plant length. About 3 out of 770 have a length as small as 8 mm. and about 3 out of 770 have a length of 16 mm. How many allelic pairs seem to be involved in the different petal length? How much does each effective allele contribute to the length of petal?

What is the difference between the conducting zone and the respiratory zone of the respiratory system? the conducting zone is a series of cavities and tubes that move air to the respiratory zone where gases exchange with the bloodstream. the conducting zone exchanges gases between the lungs and the alveoli and the respiratory zone is a series of cavities and tubes that move air to the conducting zone. the conducting zone moves oxygen into the cells and the respiratory zone takes carbon dioxide away from the cells. the conducting zone moves oxygen into the bloodstream and the respiratory zone takes carbon dioxide away from the bloodstream.

Which sentence best describes the relationship between chlorophyll and the chloroplast? a.) chlorophyll is a chemical found in a chloroplast. b.) chloroplast is a chemical found in a chlorophyll. c.) both chlorophyll and chloroplasts are found in animals. d.) both chlorophyll and chloroplasts make carbon dioxide.

The nervous system interacts with the endocrine system by a. using hormones as connections b. sending nerve impulses directly to glands c. using neuroendocrine cells as connections d. sending neurotransmitters directly to neurons