What is the sac that holds the testes and regulate their temperature?

The observations of hooke and van leeuwenhoek documenting the existence of microscopic cells formed the basis of what important theory? a. the cell theory stating that all living things are composed of cellsb. the theory of spontaneous generation, which held that life forms could arise spontaneouslyc. the theory of chemotherapy, or use of antimicrobials to destroy pathogenic organismsd. the germ theory of disease and causative agents

Identify the type of energy used in each action. the flexing of an arm muscle: a signal transduction process by a neuron: a ball at the top of a hill: 1. electrical energy 2. mechanical energy 3. gravitational potential energy

Cattle with brown fur and cattle with white fur will produce a reddish roan calf . when examined closely, the calf show about an even number of brown hairs and white hairs that give a reddish appearance when viewed from far away. the fact that both the brown fur allele and the white fur allele are expressed equally in the offspring is an example of