A object accelerates 8.0 m/s2 when a force of 2.0 Newton's is applied to it. What is the mass of the object 

The answer is 0.25 ? I think

So 1 head per squirel and 1 head per bird
4 legs per squirel and 2 legs per bird
s=number of squirels
b=birds
the equatinos should be
1b+1s=number of heads=16
and
2b+4s=number of legs=44
(note 2b=2 times b)
so we aolve

b+s=16 and 2b+4s=44
simplify the second equaiton by divideinb by 2
2b+4s=44
divide 2
b+2s=22

b+s=16
and
b+2s=22
we can actually add the two equations together with the first one made negative
-b-s=-16
b+2s=22+
0b+1s=6
s=6
subsitute
b+s=16
b+6=16
subtract 6 from both sides
b=10

10 birds
answer is c