D. fingernails
Skin, hair, and vertebrae are all the outer layer of the body and protect the body. The fingernails aren't part of that.
Answer:
D, 'cus Heterotrophs can't make their own food like plants or humans, and Autotrophs can make their own food. For example plants, or in this case bacteria
Answer:
The correct option is B.
Explanation:
Muscle tissues of the heart refers to a group of cells that are carrying out similar functions in the heart. There are three different types of muscles, these are skeletal, cardiac and smooth muscles. The cardiac muscles are found in the heart, they form the contractile wall of the heart. These muscle contract involuntarily ( that is, without any external stimulation) and they are single nucleus, striated and short.
