However, human activities generate additional 'greenhouse gases'. Globally, atmospheric concentrations of two of the main greenhouse gases, carbon dioxide (CO2) and methane (CH4) have increased over the last 150 years. Agriculture has played a significant role in this-up to 35% of anthropogenic CH4 comes from animals and their wastes (Monteny et al. 2006).
sperm, sperm cell, spermatozoan, spermatozoon-the male reproductive cell; the male gamete; a sperm is mostly a nucleus surrounded by little other cellular material. egg cell, ovum-the female reproductive cell; the female gamete.
Answer: It is a type of bacteria called Mycoplasma about a diameter of 10Âµm (micrometre). Q12: Name the smallest cell in human body. Answer: Human sperm cell about 5x3 Âµm. Q13: Name the biggest cell in human body. Answer: Human ovam about 1mm in diameter.