two
A DNA molecule consists of two long polynucleotide chains composed of four types of nucleotide subunits.
The right answer is A.
Plant species are particular in their ability to produce oxygen and carbohydrates through photosynthesis. The plant, just like the animals also needs to breathe so that these cells survive, so it is forced to take some of the oxygen and carbohydrate produced by photosynthesis to operate these cells through cellular respiration.
Two systems<span> control all physiologic processes: The </span>endocrine system broadcasts<span> it's hormonal ... </span>The nervous system exerts point-to-point over body<span> control </span>through nerves<span>. ... </span>Both nervous system<span> and </span>endocrine system<span> work together to maintain ... which </span>regulate<span> the production of other hormones throughout the </span>body<span>.</span>
<span>The epidermis is mainly a composition of cells called keratinocytes. Defensive cells are known as Langerhans cells and are one of the three types of specialized epidermal cells, The epidermis is bonded to the dermis. Hairs grow in the dermis and up to the epidermis. So, the dermis and the epidermis both have cells and hair. </span>
