4. All cells of an organism are engaged in many different chemical reactions. This fact is best supported by the
presence in each cell of thousands of different kinds of
(1) enzymes
(3) chloroplasts
(2) nuclei
(4) organelles

a time line cause it goes from 685 to 978

brain development. a child's brain undergoes an amazing period of development from birth to three—producing more than a million neural connections each second. the development of the brain is influenced by many factors, including a child's relationships, experiences and environment.

explanation:

energy per photon is e = h*c / λ  

e = 6.63*10^-34 * 3*10^8 / 6*10^-7 j = 3.315*10^-19 j  

nr. of photons = 10j / 3.315*10 = ^-19 j per photon = 3.02*10^19 photons