Why are chromosomes not always visible? a.
They are often very loosely coiled in strands of chromatin
c.
They lose pigment in sunlight
b.
They are wound very tightly
d.
They are often behind the nuclear envelope

Can someone me with these questions plz.

8.98 dm3 of hydrogen gas is collected at 38.8 °c. find the volume the gas will occupy at -39.9 °c if the pressure remains constant.

Choose an equation that represents an enzyme-catalyzed reaction. (a) enzyme + substrate → enzyme-substrate complex (b) enzyme + substrate ←−→ enzyme + products (c) enzyme + substrate ←−→ enzyme-substrate complex → enzyme + products (d) enzyme + substrate ←−→ enzyme-substrate complex → enzyme-substrate complex + products