Biology students designed an experiment to study the effects of nicotine on the respiration rate of goldfish. They counted the number of times the gills of a goldfish moved at room temperature (25 C). After this each lab group placed two goldfish into five 2000 ml beakers containing 1500 ml of water. They waited 10 minutes for the fish to calm down and begin to breathe normally. The students then used a dropper to place 20, 25, 30 and 35 drops of pure nicotine into the water of four of the beakers. The water in the fifth beaker had no nicotine added to it. While viewing the fish through a magnifying glass the students counted the number of gill movements for 60 seconds. . Which variables in this experiment should made constant in order to get reliable results

Will mark brainliest i only need the ! 1.use ten beads and a centromere of one color to construct the long chromosome. use ten beads and a centromere of a second color to construct the second chromosome in the long pair. make a drawing of the chromosomes in the space below. 2. for the second pair of chromosomes, use only five beads. 3. now model the replication of the chromosomes. make a drawing of your model in the space below. part b: meiosis i during meiosis i, the cell divides into two diploid daughter cells. 4. pair up the chromosomes to form tetrads. use the longer tetrad to model crossing-over. make a drawing of the tetrads in the space below. 5. line up the tetrads across the center of your “cell.” then model what happens to the chromosomes during anaphase i. 6. divide the cell into two daughter cells. use the space below to make a drawing of the result. part c: meiosis ii during meiosis ii, the daughter cells divide again. 7. line up the chromosomes at the center of the first cell, one above the other. separate the chromatids in each chromosome and move them to opposite sides of the cell. 8. repeat step 7 for the second cell. 9. divide each cell into two daughter cells. use the space below to make a drawing of the four haploid cells

What is the average speed of a car that traveled 300.0 miles in 5.5 hours

Guinea pig coat color is determined by a single gene. the allele for black coat color is dominant to brown. in a cross between twoblack-haired guinea pigs, 20 offspring are born. if both parents were heterozygous, probability would predict that approximately howmany of the 20 offspring would have brown hair?