Describe how you produced summated contractions with the isolated muscles and how you produced a tetanus contraction. explain how summation of twitches is accomplished in vivo and how a sustained, complete tetanus contraction is produced.

Two male mice, which we will call male a and male b, are both phenotypically normal. male a was from a litter that contained half phenotypically normal mice and half dwarf mice. the mother of male a was known to be homozygous for the normal igf2 allele. male b was from a litter of eight mice that were all phenotypically normal. the parents of male b were a phenotypically normal male and a dwarf female. male a and male b were put into a cage with two female mice that we will call female a and female b. female a is a dwarf and female b is phenotypically normal. the parents of these two females were unknown, although it was known that they were from the same litter. the mice were allowed to mate with each other, and the following data were obtained: female a gave birth to three dwarf babies and four normal babies. female b gave birth to four normal babies and two dwarf babies. which male(s)mated with female a and female b? male a with both females male a with female b, and male b with female a male a with female a, and male b with female b could not be determined male b with both females

2. how does the miller-urey experiment fall short of demonstrating that life can arise from inorganic molecules? explain. a. it doesn't show a leap between a collection of amino acids and a single-celled organism. b. it recreates the conditions that existed at the earth's beginning, but no molecules form as a result. c. it doesn't provide evidence of the formation of amino acids. d. it doesn't show how multicellular organisms developed from unicellular organisms

Penelope studies how the structure and function of the nervous system is related to behavior. she is a psychologist