Insects, and some other invertebrates, exchange oxygen and carbon dioxide between their tissues and the air by a system of air-filled tubes called tracheae. Tracheae open to the outside through small holes called spiracles.
Answer:
A chromosome is a deoxyribonucleic acid (DNA) molecule with part or all of the genetic material (genome) of an organism. Most eukaryotic chromosomes include packaging proteins which, aided by chaperone proteins, bind to and condense the DNA molecule to prevent it from becoming an unmanageable tangle. This three-dimensional genome structure plays a significant role in transcriptional regulation.
The answer is fertilization.
Fertilization is the process in which two gametes fuse which
first creates a zygote and then leads to the development of an embryo. Pollination is a transfer of male pollen to the female reproductive organ. By reaching there, male gamete and female gamete will fuse which represents fertilization. So, pollination is <span>an important step in the fertilization of flowering plants.</span>