Describe the cytological observation that suggests that crossing over occurs during the first meiotic prophase.

Name the following: (a) category of pathogen that causes diseases, like common cold and mumps. (b) the microorganism that requires a host to produce.

How do all types of diffusion/passive transport actually ‘work’ without using even the smallest amount of cellular energy?

Pulmonary arteries carry highly oxygenated blood. true or false?