<span>-Carbohydrates. Carbohydrates are comprised of carbon (C), hydrogen (H), and oxygen (O) molecules.
-Proteins. Proteins are comprised of amino acids.
-Lipids. A wide variety of biomolecules including fats, oils, waxes and steroid hormones.
<span>-Nucleic Acids.</span></span>
Answer:
The circulatory system has evolved over time from simple diffusion through cells, in the early evolution of animals, to a complex network of blood vessels that reach all parts of the human body. Made of specialized and unique cardiac muscle, it pumps blood throughout the body and to the heart itself.
Claps shut at birth. Evolutionary changes in the vertebrate heart are tied to change from single to double-circuit heart, with increased separation of oxygenated and deoxygenated blood, allowing more efficient respiration and circulation to fuel high activity and increased oxygen demands associated with endothermy.
Answer: 100 grams of the parent isotope will remain after one half life.
Explanation:
Mass of the isotope present at initial stage = 
The mass of the parent isotope left after the time ,t=N
Time taken by the samle ,t = 
The half life of the sample :
![\ln[N]=ln[N^o]-\frac{0.693}{t_{\frac{1}{2}}}\times t_{\frac{1}{2}}](https://tex.z-dn.net/?f=%5Cln%5BN%5D%3Dln%5BN%5Eo%5D-%5Cfrac%7B0.693%7D%7Bt_%7B%5Cfrac%7B1%7D%7B2%7D%7D%7D%5Ctimes%20t_%7B%5Cfrac%7B1%7D%7B2%7D%7D)
![2=\frac{[N_o]}{[N]}](https://tex.z-dn.net/?f=2%3D%5Cfrac%7B%5BN_o%5D%7D%7B%5BN%5D%7D)
![[N]=\frac{N_o}{2}=\frac{200 g}{2}=100 g](https://tex.z-dn.net/?f=%5BN%5D%3D%5Cfrac%7BN_o%7D%7B2%7D%3D%5Cfrac%7B200%20g%7D%7B2%7D%3D100%20g)
100 grams of the parent isotope will remain after one half life.
