Strontinum-90 is produced as a nuclear fission product of uranium in both reactors and atomic
bombs. It has too many neutrons, and it decays
with a half-life of about 29 yr.

(need help with a and b)

find the surface area of the sphere to the nearest square unit. use a calculator.

a. 254 in.2

b. 64 in.2

c. 127 in.2

d. 1,018 in.2

the best answer for these questions would be:

1.            c. is smaller

2.            d) concrete operational

3.            b) interaction with the environment – the children interact with their environment can them learn more.

4.            a) parents who reason openly with children can limit a child’s cognitive ability.