Answer:
phospholipids and proteins
Answer:
Each time a cell prepares to divide into 2 new cells, it must make a new copy of the DNA in its chromosomes. This process is not perfect, and errors can occur that may affect genes within the DNA. Cancers can be caused by DNA mutations (changes) that turn on oncogenes or turn off tumor suppressor genes.
Explanation:
Answer:
The first human ancestors appeared between five million and seven million years ago, probably when some apelike creatures in Africa began to walk habitually on two legs. They were flaking crude stone tools by 2.5 million years ago. Then some of them spread from Africa into Asia and Europe after two million years ago.
Answer:
B
Explanation:
Y chromosomes are the male chromosome. A person with an XY sex chromosome pair will be male while that with an XX sex chromosome pair will be female. This is because the Y chromosome has a male-determining gene called the SRY. This gene is responsible for the development of testis.
