A student is creating an electromagnet for an investigation. Which feature of the electromagnet will least influence the magnetic force? A
the material of the core
B
the brand of the battery
С
the number of wire coils
D
the che of the power source

.) the observation by semmelweis that more mothers died of childbed fever when their doctors also worked in the morgue

myth. it was once thought that animals, including cats and dogs, could only see in black and white. however, scientists have proven this to be a myth. in all animals, including humans, the perception of colour is determined by the presence of cells in the eye called cone photoreceptors.