A and D seem like the best answers
Stomata are tiny pores present in the leaf that allows gas exchange and is where water vapour leaves plants and carbon dioxide enters. Special cells called guard cells present in the stomata, control each pore's opening or closing. When stomata are open, transpiration rates increase; when they are closed, transpiration rates decrease.
Answer:
D. Transport of oxygen through a placenta to a fetus.
Explanation:
Zygotes are fertilized egg cell, zygotes aren't produced in the ovaries but ovums or egg cells are produced in the ovaries. So option A is false.
Fertilization is internal not external in human. Option B is wrong.
Production of milk happens in the mammary gland (the breast) not in the reproductive system. Option C is false.
Transport of oxygen through a placenta to a fetus. The placenta is a vascular organ which is implanted in the wall of the uterus (a part of the female reproductive system) and links to the foetus through the umbilical cord.
The Earth was first considered habitable when we discovered that it was Microbial organisms that started the process. I would go with D.
Answer:
They lack a nucleus, but they do have ribosomes.
Explanation:
Prokaryotes are unicellular organisms that lack organelles or other internal membrane-bound structures. Therefore, they do not have a nucleus, but, instead, generally have a single chromosome: a piece of circular, double-stranded DNA located in an area of the cell called the nucleoid.
