There are 12 pairs of curved bones called X in our chest region. One end of bones X is joined to
backbone and their other end is joined to bone Y in
front to form a box-like structure Z. This strong box
like structure protects the delicate internal organs P and
Q.

What are X, Y and Z?
Name the organs P and Q

Describe the response the kidneys have to dehydration and excessive water intake. what happens to the concentration of urine in each case ?

Some birds look for food near cattle and other livestock. the movement of the cattle churns up the ground, making insects available to the birds. the cattle appear to be unaffected by the presence of the birds. what kind of relationship exists between the birds and the cattle? o a. parasitism o b. commensalism o c. predation o d. mutualism

The activity of the modern sample is 1.10 bq . how long does that measurement take?