Which pair below describes isotopes of the same element? a) an atom with 6 protons and 8 neutrons - an atom with 8 protons and 6 neutrons b) an atom with 6 protons and 6 neutrons - an atom with 6 protons and 7 neutrons c) an atom with 8 protons and 8 neutrons - an atom with 7 protons and 8 neutrons d) an atom with 7 protons and 6 neutrons - an atom with 6 protons and 6 neutrons

B)an atom with 6 protons and 6 neutrons - an atom with 6 protons and 7 neutrons

Explanation:

Isotopes are elements which have same atomic number but different mass number.

Mass number is defined as the sum of number of protons and neutrons that are present in an atom.

Mass number = Number of protons + Number of neutrons

Atomic number is defined as the number of protons or number of electrons that are present in an atom.

Atomic number = Number of electrons = Number of protons

Thus isotopes of same element must have same number of protons and different number of neutrons.

The only combination that fulfil this criteria is : an atom with 6 protons and 6 neutrons - an atom with 6 protons and 7 neutrons

cell differentiation  is how generic embryonic  cells  become specialized  cells. this occurs  through a process called gene expression. gene expression is the specific combination of genes that are turned on or off (expressed or repressed), and this is what dictates how a  cell  functions.

explanation:

when jerome paddle in flowing river towards east the net speed of jerome will increase

so the net speed of jerome will be given as

now the speed of paul will be same as it is given as he is running on the ground

so

so here we can say since the speed of jerome is more so he will win the race

now as we know the distance so the time difference is given as

so jerome will reach first and the time difference will be 203.55 s or 3.4 min