A woman with attached (recessive) earlobes has a child with a man who is heterozygous for earlobes.

What are the odds the child is a female with attached earlobes?

50%

Explanation:

The mother's genes are aa, and the father's genes are Aa.  When you do the punnett square you get the following in the square:

Aa    aa

Aa    aa

The only way a child will have attached earlobes is to be aa.  There are 2 possibilities out of 4 total.  2/4 = 50%.  Thus for a child to have attached earlobes is 50%

the answer to your question is sperm

layer 3 is younger than layer 6.