The Precambrian time refers to the time 4.5 billion to 542 millions year ago. This period is characterized by having reduced atmosphere and included reduced compounds. Scientists believed that atmosphere at that time was devoid of free oxygen and CO2 was present in excess. Before the complex life evolved on the Earth, the Precambrian Earth's ocean contained dissolved carbon dioxide.
<u>Answer:</u> They have the maximum number of hydrogen atoms.
<em>Saturated fatty acids have the maximum number of hydrogen atoms.</em>
<u>Explanation:</u>
A fatty acid that doesn’t contain any double bond between carbons in their molecular structure is known as saturated fatty acid. They are also incapable of absorbing hydrogen in their molecular structure thus the name.
Saturated fatty acids are generally found in animal fats like butter, milk and dairy products. Because of the higher melting point of those fatty acids, they are generally found in solid state at reem temperature.
Answer:
Petiole
Explanation:
The petiole is the part of the leaf that attaches the leaf to the main stem of the plant. Depending on the leaf structure of the plant, some leaves may be devoid of a petiole, and be regarded as apetiolate.
Answer: Option B.
Help control weeds and insect pests.
Explanation:
Insect are the largest group of organisms on Earth. They belong to the phylum arthropoda and class insecta. They have hard exoskeleton, antenna, they have three pairs of legs and their body is divided into head, thorax and abdomen.
Insects are biological resources in that they help control weeds and insects pest.
The insects are use as weed control in that they feed on the weeds i.e they use the weeds as food there by absorbing the nutrients for weeds development, which lead to their inability to survival. Some canivorous insects feed on insects pest i.e use they as food, thereby reducing their harmful effects in the ecosystem.
