A cross between two different lines and/ or genes that differ in two observed traits.
<span>LD
means lethal dose. LD50 is the amount of a material, administered at once to
cause the death of half (50%) of a group of test organisms. A test which shows that LD50 of a certain
chemical is 20 mg per kg means that 20 milligrams of that chemical for every 1
kilogram body weight of the test animal when administered in one dose, causes
the death of 50% of the test group.</span>
Answer:
All of them should be checked
Explanation:
If you make a punnet square you will have F and f lining the top and sides. The inside boxes will be FF, Ff, Ff, and ff. FF and Ff are long fins and ff is short fins so both are possible. Hope that helps good luck.
D. all of the above because
Repair of damaged tissue.
Growth of an organism.
Replace old and dying cells.
