Variation occurs when chromosomes are shuffled in .

How many cells are our body made of ? ♡

An example of internal feedback working to maintain homeostasis is your a. decreased respiration rate when you are studying b. decreased heart rate when you are sad c. increased respiration rate when your muscles need more oxygen d. increased heart rate when your lungs need more oxygen

Aperson with age is more likely to catch diseases that healthy people usually don’t catch.what are these infections called?