All cells have a cell membrane. its basically what protects the cells from getting toxins that are sometimes entering your body. without a membrane on all cells, you would get sick a lot!!
Answer: A. ancestral trait
Explanation:
Bipedalism can be define as a form of terrestrial locomotion, in which the organism moves with the help of two rear limbs or legs. Typical bipedal movements includes the hoping, running and walking. The evolution of the human bipedalism occurred in primates in about 4 million years ago with Sahelanthropus (oldest human ancestors or African Apes). The human ancestor Sahelanthropus led to the morphological alterations in the human skeleton including changes in the bones such as size of the bones of the foot, knee size, shape and orientation of the vertebral column, and leg length. All these changes contributed to the bipedalism.
1. The correct answer is option A
The thickest layer is Dermis which is made up of two layers papillary and reticular. The reticular dermis is the lower layer of the dermis and is made up of dense irregular connective tissue featuring collagen fibers.
2. The correct answer is option E
Bone is composed of fibrous and mineralized connective tissues which is enriched in collagen and calcium phosphate.
3. The correct answer is option C
Muscles are composed of two major protein filaments: a thick filament composed of the protein myosin and a thin filament composed of the protein actin. These two filaments slide over each other to repetitively contract the muscles.
Answer:
The correct option is c ( <span>sexual reproduction joins two cells that each have half the total chromosome number).
Reason:
Meiosis occurs only in reproductive cell in which the number of chromosome reduce to half. This phenomenon is very imoportant and essential for maintaining the number of chromosomes in species.</span><span />