Adoctor finds that the mammary glands of a woman are not functioning due to a genetic abnormality that influences the structural design of the thoracic cavity. this is likely the result of a mutation:

The result of a mutation on a Hox gene.

Explanation:

The mammary gland of a women is not functioning properly due to the genetic abnormality which is caused due to mutation in the hox gene.

The hox gene helps in the thoracic development which later on provides support to the mammary gland.

The gene is responsible for the development of the structure and and mutation in the gene is responsible for genetic abnormality that influences the  mammary glands of human beings.

the answer for apex is "1 and 6"

the answer is: the „power stroke“ step.

muscle contraction can be divided into a few steps:

1. the release of ach (acetylcholine) in the synaptic cleft, binding of ach for its receptor and consequently opening of the ca channels.

2. the release of ca, binding of ca for the troponin

3. troponin shifting the tropomyosin, which was blocking the active site on the actin

4. myosin heads attaching to actin by breaking down atp to adp+ pi

5.   formation of the ‘cross-bridge’ on the active site of the actin filament by myosin head

6. “power stroke” -the cross bridge pulls actin, which slides over the myosin

9.     7. the release of adp completes the cross-bridge movement and atp attaches to myosin, breaking the actin-myosin cross bridge.