有關生物的問題

Excretion is the removal of metabolic waste produced by metabolism in the
body but defaecation (egestion) is the removal of undigested materials
from the anus in the alimentary canal. In other words, metabolic
wastes are produced by metabolic chemical reactions in body but
faeces are not.
( Metabolism are reactions carried out through the catalyst of reactions by
enzymes in body )

For example, urea is formed by the breaking down of excess amino acids
in liver and is produced into urine for excretion
while carbon dioxide is also produced from respiration of cells.
Since urea and carbon dioxide are produced by metabolism, they are
metabolic wastes and are removed by excretion.

However, faeces are the remaining materials after digestion and
absorption of food in the alimentary canal,
which are the undigested materials.
They are semi-solid brown mass including undigested food and dead
and live bacteria, which are not produced by metabolism.
They will be finally stored in the rectum and removed in the anus.
( P.S. There is removal of metabolic waste involved in defaecation,
which is the removal of bile pigments, since bile pigment is an
excretory product. )

如果你是初學生物學，只在讀The seven characteristics of living
organisms時，請不要擔心，因在後面的課題，例如是Nutrition in humans
和Homeostatics的課題會有這方面更詳細的講解。

排遗是动物排出废物的一种现象，一般指排除未消化的食物残渣，如蛔虫、鸟类等的排遗，粪便是属于排遗作用。

排泄作用是指生物體將代謝廢物排出體外的作用，是所有生物生存的必要過程，如排汗。

概念不要搞错。。。

1. 糞便是 "排遺" 作用. egestion

糞便是你食咗入身體, 但不能被分解和吸收的垃圾. 所以根本就是外來的東西, 不是身體自己細胞製造出來的東西.

試想下, 你吞咗粒鑽戒入口, 粒鑽戒就沿食道, 胃, 小腸, 大腸, 肛門, 走番出來. 從來無入到去你身體, 例如, 手腳的細胞.

2. 排泄物, 你只要記住以下幾種:
a. 汗液, 尿液 (含尿素, 是身體肝細胞, 把多餘的蛋白質分解後製造出來的)
b. 膽色素 (是身體肝細胞, 把紅血球分解後, 剩下的無用物質)
c. 二氧化碳 (是身體各個細胞經呼吸作用, 產生的無用物質)

換句話講:所有排泄物係產生by body cells

詳見會生物書book3, 關於體內平衡, 一課

米田共係排遺作用黎ga~~
排泄作用大多數都係講細胞整出黎ge野
咁d便便都唔係cells整出黎ge

糞便只不過係'排泄作用'既完成物,
排泄作用-大便(要用動詞!!)
小便
排汗
你可能答錯左個文法~正如sweat汗,不等如sweating流汗/排汗!

不如你問下你老師，既然糞便唔係排泄作用，甘係咩乜？

因為排泄作用不是化學反應..
使用化學反應排泄既有:出汗 ,etc.