How are fish hearts and mammal hearts different?

Which of the following statements about brain development and early childhood is true? the brain of a 5 year old is 60 percent the size of an adult brain the overall size of the brain does not increase dramatically from ages 3-15 by the time a child is 3 years of age, the brain is 25 percent of it's adult size the development that occurs inside the brain ends at the onset of adolescence

Enzymes are both ph and temperature specific. seen here are the reaction rates of three common digestive enzymes. based on the data, which enzyme's optimum activity occurs in a basic environment while another's is very acidic?

The human population is growing increasingly sharply in blank countries