I answered the question before but ill try to explain more. You know after 5 seconds they are going 60km/h, if you want to know how many km/h they are going per second (that would be their acceleration) you would take how fast he is going after those 5 seconds (60km/h) and divide it by how many seconds it takes him to get to that speed (5sec) and your answer would be how many km/h they can get to in one second (their acceleration).
20. d
21. a
22. c
23. b
24. c
25. b
26. d
27. a
A substance that can not be broken down into any simpler substance is called an element.
Antigens: Antigens are substances that cause an immune response in the body by identifying substances in or markers on cells. Your body produces antibodies to fight antigens, or harmful substances, and tries to eliminate them.
Antibodies: Antibodies are proteins which belong to a class known as immunoglobulins. They are made up of chains of amino acids joined by peptide bonds.
Cellular immunity: Lymphocytes act against target cell,Acts directly by killing infected cells,Acts indirectly by releasing chemicals that enhance inflammatory response; or activating other lymphocytes or macrophages.
Hope this help!!
Answer:
The statement World empires in Asia that relied upon large-scale irrigation and drainage schemes for agricultural productivity are known as hydraulic societies is true.
Explanation:
Agricultural productivity is measured as the ratio of agricultural outputs to agricultural inputs. While distinct goods are generally measured by weight, their changing concentrations make calculating complete farming output problematic. Since 1948, U.S. agricultural productivity has more than doubled, enabling farmers to feed more people with less land and labor. Agricultural output growth is attributed to the growth in total inputs used and in technology advancement, or total factor productivity. The hydraulic society is the Societies in which institutions are closely linked to the development and control of systems of irrigation and, sometimes, water-based transport.
