When one extra chromosome causes a number of difficulties for the afflicted individual a. pleiotropy b. epistasis c. genome d. down syndrome

In sexual reproducing animals once fertilization of the egg takes place, the exists as a single cell until cell division begins. a) egg b) larva c) sperm d) zygote

Is there any solid scientific evidence that humans have been cloned?

Ascience research group is testing a new type of plant food. one trial is conducted in a controlled experiment. the data from the trial show that the plant that received the new food grew faster than the control plant. the group announces that the new plant food makes plants grow faster. what is the main weakness in this scientific claim?